I find painting with oils is a pain.  They are easy to use only if you use them alla prima; this means putting them down in one layer without over-painting, and using a minimum of painting mediums – much like theImpressionists did.  But I like to paint in many layers using transparent and translucent glazes and scumbles so I can achieve a variety of effects.  It could take me several weeks to complete a piece while I wait for the individual layers to dry.  Add to this the vast array of possible painting mediums and the care needed to use them properly without compromising the integrity of the paint film, and I want to go running back to acrylics.  But there are some luscious effects you can achieve with oils that can never be duplicated by any other medium…

Our modern tube oil colors are made of a simple combination of raw linseed and/or safflower oil, and the powdered pigment.  But this was not always the case.  Painters knew about drying oils like linseed oil for centuries before they actually started mixing powdered pigments with them to make paints.  They would use them occasionally to glaze over areas of tempera paintings, but to actually make a painting using oil as the binder for the pigments like we do was not considered a good idea.  Not only do these oils dry slowly, but they dry faster with some pigments than they do with others!  So you can’t paint a fast drying color over a slow dryer, you know, the whole ‘Fat over Lean’ thing (see “Technical Corner” in the April 2000 issue).  The other problem that these old painters noticed was that drying oils become increasingly dark and yellow with age.  So why have oil paints been the paint of choice for the last 600 years or so?  Because for the first 450 artists rarely used oil paints – they used Resin-Oil paints!

Making paints with oils really began in the 14th century when it was discovered that adding zinc and lead pigments to the oil made it dry faster.  Also, the technology to distill solvents like turpentine was developed.  Turpentine could be used to thin the oil and a thinner layer of oil paint dries faster.  But more importantly, turpentine provided the means to dissolve hard resins like Copal, Mastic, and Damar.  These resins dry fast, hard, and clear, and they don’t yellow much with age.  By themselves they are too sticky to paint with and dry too hard and brittle.  Linseed oil, on the other hand, dries slowly and yellows with age, but it is durable and flexible and is wonderful to push around under the brush.  The old painters realized that the two combined would create a fast drying, clear paint that could make beautiful transparent glazes and sumptuous blended tones and colors, unlike anything anyone had been able to do with tempera paints.  These resin-oil paints were far more brilliant than straight oil paints and the colors would dry faster and more evenly so the ‘Fat over Lean’ problem was effectively eliminated.  It is also unlikely that these painters used raw oil to make their paints and mediums like we do today.  Instead, they would have used Stand Oil and Sun Thickened oil.  These oils are linseed oil (or another drying oil) that have been partially oxidized and polymerized through heat or exposure to sunlight.  When a drying oil is polymerized in this way it dries faster, becomes more flexible and durable, and yellows less with age.

Jan Van Eyck (1385-1441) and Antonello De Messina (1430-1479) were among the first to exploit the potential of this new medium and the novel effects they achieved in their paintings were considered miraculous.  Most of these early ‘oil’ painters continued to use tempera paints in combination with the new Resin-Oil paints.  In this mixed technique the painters would apply resin-oil glazes over tempera underpaintings and then alternate between crisp tempera paint details and transparent glazes.  By the time the great Renaissance masters likeTitian (1487-1576) and Tintoretto (1518-1594) started painting they were using a combination of drying oils, beeswax, and resins to make their paints and mediums.  Rubens (1577-1640) claimed a painter could finish a painting within a couple of days, complete with all the glazes and translucent effects!  He sure wasn’t using the same tube oil colors and painting mediums we get at the art store!  It is little wonder that modern painters have had so much trouble trying to duplicate the effects of the Old Masters.

So why are our tube oil paints made with only raw oil?  The most important change happened in the 19th century when manufacturers started making paints for artists and packaging them in collapsible tin tubes.  Because of packaging and shelf life Resin-Oil paints gave way to straight oil paints.  As artists today we have access to a wide range of excellent products that is unmatched at any time in the history of art.   Still, this is one trade off that has not served us well.   The Schmincke company is the only one I know of that makes Resin-Oil paints.

If you like to grind your own paints using the powdered pigment then you can find a good recipe to make your own Resin-Oil paints.  It is not enough to just add resin to your tube oil paint.  You would not get a balanced formula.  I use a simple method to alter my tube oil colors.   I spread them out on a paper towel for a few minutes so that some of the oil gets soaked out of them, I then replace the oil with a resin rich painting medium.   It is not the perfect solution but it is an improvement.  If Da Vinci had our choices he would probably still mix his own paints, or buy the more expensive Resin-Oil paints – I think that’s what I’ll do.

There is a lot of confusion over what “fat over lean” means and how this rule applies in oil painting.  It has to do with the drying rate of the different colors in oils.  First, consider how oil paint dries.  Unlike water media paints like watercolors and acrylics that dry thru evaporation of the water, oils dry thru a complicated chemical process that involves oxidation –  polymerization.  The paint actually absorbs oxygen and expands at a certain point during the drying.  Imagine then if a thin, dry layer of paint sits on top of a layer that is moving and expanding – the result is cracking and lifting of the top layer.  Also, ‘fat’ paint dries to a more smooth glossy finish while ‘lean’ paint has a rougher more absorbent surface, more suitable for subsequent layers to attach themselves to.  This is why we hear “be sure to paint “fat” over “lean” to avoid cracking.
Different pigments absorb varying amounts of oil to reach optimum consistency.  A “fat” paint is one that has a high oil content, a “lean” color has less oil.  The idea is that a color that is high in oil will dry slower so it is not recommended to place it under one that is lean, or a faster dryer.  So which paints are fat and which are lean?  Well, usually the transparent colors contain more oil while the opaque ones have less.   Unfortunately some transparent colors, like Prussian blue, are high in oil (fat) but are rapid driers while some opaque colors, like Yellow Ochre, have less oil but are slow driers nonetheless.
The most important concern is not whether the paint is fat or lean but whether it is a fast or slow drier.  You can find a chart of “pigments in oils” in Ralph Mayer’s excellent book:  The Artist’s Handbook.  The best way the learn how to apply this rule is to do a simple drying test with your colors.  Paint out a swatch of every color, not too thick and the same thickness for every color, and check them all periodically over a few days and note which ones dry faster and which slower.  Give them a ranking of: 1.  Fast dryer (a day or two) 2.  Average dryer (about a week) 3.  Slow dryer (a couple of weeks) 4.  Very slow dryer (three or more weeks).  Use this chart as a reference when you paint.
Here are a couple more recommendations when you are painting in oils to avoid cracking from slower drying layers in the underpainting:

1. Paint in thin layers in the underpainting and add extra turpentine to the paint or to the medium to help it dry faster.
2.  If painting in multiple layers it is safest just to wait for the underpainting to dry. Many artists will work on several    paintings at a time over a period of weeks.

Good day Mr. Langevin,

I have read in the FCA review that you recommend the “Liquin” (made by Winsor & Newton) medium for oil painting and I would like to try it.  I am not sure how to use it.

Is it better to dilute it with solvent or turpentine?  If yes, in which percentage? Or should I use it pure, mixed with colour, and in which quantities?

Should I add more medium at each additional coat?  I work thin.  How long should I wait to put on another coat?  This product is very new for me.

Is it dangerous for cracking, after many years if I use it all the time or if I don’t wait long enough? Also, I don’t want to have shininy and mat spots of colors using this medium. What I can do?

Thank you in advance for your answer,

Hi,

An oil painting medium like Liquin is excellent to use to thin your colors to paint fine detail or to make transparent passages (glazes).  You don’t need to use it all the time, or add more to each subsequent layer.  Just use it when you need it to create the effect you want.  And only use as much as you need to get the job done.  It is best to add a little at a time to your paint on the palette until the paint is at the right consistency and you get the effect you are looking for.  This will assure a more controlled use of the medium than would a method of dipping your brush in it or mixing it directly on the canvas, for example.

It is not necessary to add solvents like turpentine to the medium.  Most mediums are engineered to give the desired result without thinning them.  Mediums like Liquin are invariably a mixture of a resin and a solvent so adding more solvent will upset the balance of the mixture and create unpredictable results for your painting.

You can paint over it right away or wait until it is dry.  If you prefer to paint over a dry surface a thin layer of paint with the Liquin added will usually be dry enough to paint over within a few hours.

The Liquin is not dangerous for cracking as long as you don’t use too much, especially in the under-layers of the painting.  Like I said, use only as much as you need to achieve the desired effect.

You will have shinny and matte sections in your painting even if you don’t use any medium, different colors (pigments) are more glossy and transparent than others.  Of course, using a medium like Liquin makes any color more shinny.  Most painters put a final picture varnish over their oil paintings, not only to protect the painting, but to regulate the gloss of the image as well.

Hope that helps, have fun.  David

Hi David,

This may seem to be a very elementary question but what characteristics mark the visual difference between an oil or acrylic painting? If I were to have one of each – side by side – how would I be able to differentiate and tell which was the oil and which was the acrylic – especially if the paintings are 20 – 25 years old.

Thank you for your response, Kathy

A.  It is not an elementary question at all Kathy.  In fact it is often hard for experts to tell them apart.  Other times it can be quite simple, depending on the style and techniques used.  It would actually be easier if you had an oil and an acrylic painting side by side so you could compare differences.

There are many factors involved.  Some things to look for would be yellowish brown oil stains on the back of the canvas where oil may have soaked through. That is a sure give away that the painting was done in oil.  Brush marks are more prominent in oils as well.  Smooth, soft blended tones and edges are a sign that oils have been used.  If there is any yellowing or cracking in the paint film that probably means it is an oil painting.

Acylic paintings tend to have a more synthetic look.  The paint will be quite hard on an older oil painting whereas acrylic paint is thermoplastic so it will get softer when warm.  If you can dig your nail into the paint and it is not hard, that means it is likely an acrylic piece.

Hope that helps Kathy, thanks for the question.  David

Hello David,

My name is Linda, I am writing from Toronto, Canada.  I have recently started painting with oils, so please, pardon my ignorance. I am using linseed oil to thin out my paint. I painted the background 1st, but I am finding that it is still not dry after 3 days.  Is this normal? Or am I using too much linseed oil? How do I know when I am using too much or too little? Or is it a factor at all? I would like to know what the general amount of time it takes for a thin layer of oil paint to dry?

Thanking you in advance for your co-operation.

Hi linda,

It is not a good idea to thin your paint with linseed oil.  It will drastically slow the drying time.  Because of the excess oil used, subsequent layers will not stick well to this glossy (“fat”) layer either.  The extra oil will also make the paint yellow more as it ages and it may also cause wrinkling.  If you are painting on canvas, more oil will soak through to the fabric and cause it to rot prematurely.

It is much better to use an oil painting medium to thin your paint.  There are many good quality ones available at the art supply store.  My favorite is called Liquin, made by Winsor & Newton.  Some “fast drying” mediums will even speed up the normal drying time of the paint.  Some colors dry faster than others and the addition of a good quality medium will regulate this as well.

If you do not want to use a painting medium then you can thin your paint with a solvent (mineral spirits or turpentine) or just apply a very thin pure layer of color.  Don’t use too much solvent either or your paint layer will be too ‘lean’ and loose its flexibility – causing cracking and flaking.

Have fun painting, David

Hi, I was in your demo class today and you were talking about medium
recipes for oils. Could you please send them to me.
Sincerely, Lorraine
P.S. I really enjoyed your demo.

Thanks Lorraine.  I have been asked on several occasions to discuss the use of painting mediums with oil paints, so here it is…

Many artists simply use the paints straight from the tube, painting alla prima.  This is a fine way to paint.  Still, the full range of possible effects in oils can only be achieved by modifying the paint with some sort of painting medium.

Some painters simply thin their paints with solvents like turpentine for washes and fine detail while others use straight linseed oil, or a simple combination of the two.  In fact, some inexpensive commercial painting mediums are made of these two ingredients only.  But straight linseed oil and turpentine are not good choices to use as painting mediums, alone or together.  Because modern tube oil colors are made with only Linseed oil (and sometimes safflower oil) they are already proportionately too high in oil content, so you don’t want to add more!  Linseed oil dries to a flexible, durable film but unfortunately it also darkens and yellows with age, and takes your colors with it!  Excess oil also slows down the drying time, which can cause cracking with certain pigments and may also cause the paint film to wrinkle.

Adding only solvents like turpentine or mineral spirits to dilute the paint weakens the paint film by spreading the oil too thin.  A thin layer of ‘lean’ paint is no longer flexible and is likely to crack.   The lack of oil in the paint film also makes the colors dull and opaque, and the paint film too absorbent.  Any subsequent layers of paint put over top of this ‘lean’ layer will also darken as too much of the oil will soak into the thinned-out layer underneath.

There are some good ready-made painting mediums on the market but they do not normally list the ingredients.  Buy good quality mediums (the expensive ones) and you will probably get good results.  Winsor & Newton makes a good painting medium called Liquin, it is made with an alkyd resin.  Alkyd resin is used in commercial house paint as well.  It is chemically compatible with oil but dries fast and clear.

It is easy to make your own painting medium and most art supply stores carry the raw ingredients.  The advantage of making your own is that you know what you are getting and you can make mediums to suit your own needs and painting style.

A good painting medium has at least three ingredients:  oil, a solvent, and a resin.  I don’t recommend making mediums with anything but polymerized oils (stand oil, or sun-thickened linseed oil) because they dry faster, clearer, and form a more durable paint film than raw linseed oil.  Pure Gum Spirits of Turpentine or Rectified Turpentine are the only solvents that should be used in a painting mediums.  Unpurified solvents like those available in hardware stores will have unpredictable results.  Also note that natural resins like Damar cannot be diluted with mineral spirits.  Damar resin is considered the best all round resin for oil painting mediums.  Masticand Copal are also used to make mediums.  A drier like Cobalt Drier can also be added in small amounts to the medium.

Here are some guidelines to remember when making your own mediums.  Use them to help you make adjustments in your recipes to suit your style or a particular effect you want to achieve:

  1. Polymerized oil (Stand Oil, Sun-Thickened Linseed Oil):  oil gives the medium elasticity and durability.  With too much oil in the medium the paint film will dry slowly and darken and yellow with age.  Not enough oil and the film will be too brittle and will tend to crack and flake.

2.  Resin (Damar, Copal, Mastic, Venice Turpentine):  The addition of resin to the paint film makes the colors brilliant and more transparent.  The resin speeds up the drying time and makes all colors dry at similar rates.  Not enough resin in your medium and the paint will dry slowly and it will look duller.  Too much resin and the paint will be too sticky to handle and the dried paint film will be too brittle and hard.  Copal is a very hard resin and does not readily dissolve in turpentine.

3.  Solvents (Pure Gum Spirits of Turpentine or Rectified Turpentine):  Solvents help make the medium more manageable by thinning it out.  It also helps to blend the resin with the oil.  Too much turpentine will make the medium thin and it will lose its luster, adhesive strength, and flexibility.  Not enough solvent makes the medium too thick and difficult for use in glazes and fine detail painting.

Here is a recipe for a good all round oil painting medium from Ralph Mayer’s “The Artist’s Handbook”:

Damar varnish (5lb cut) – 1 fluid oz.
Stand oil – 1 fluid oz.
Pure Gum turpentine – 5 fluid oz.
cobalt drier – 15 drops

Do not add more Cobalt Drier if you want a faster drying medium, excess dryer may cause the paint film to shrink and crack.  Instead, increase the amount of turpentine.  Another recipe that I like uses Venice Turpentine (a resin) instead of Damar resin.  This one dries very clear and brilliant and is good for glazes.

1 part stand oil
3 parts venice turpentine
1-3 parts turpentine (can be varied according to fat over lean principle)

A variation of this that would dry faster is to mix 2 parts Venice Turpentine and 1 part Damar to 1 part stand oil.  Warming the stand oil and Venice Turpentine is necessary to mix them easier.

Hello,

I have just purchased a large oil painting from
1890 which I believe to be valued at approximately 8000.00.  I am entirely
inexperienced in art work, and my question is this—-The painting is
matted and framed under glass.  Am I correct in believing that the more
appropriate way to display and preserve the painting is exposed to the air, and
not under glass?  What would you advise?

Thank you for any help you can give.

Normally oil paintings are varnished and framed without glass, but not because it is a better way to preserve them.  It is not unusual to see very valuable or sensitive paintings framed behind glass (the Mona Lisa is a famous example of this).  The varnish serves as a protective layer so the painting can be cleaned without damage, but it only protects the surface of the painting.

If it is framed behind glass this may indicate that it would not be safe to expose it to air.  Perhaps the painting is done on an unstable surface like paper or cotton that would deteriorate much faster if exposed.  It may also be that the painting cannot be cleaned as it is too sensitive to solvents, or glass was simply chosen instead of varnish as a protection.

In any case, any painting will last longer under glass, it just may not display as well.

Hi David

Is it a bad thing to frame oils behind glass; I have heard
that it will make the painting “sweat” and it is not a good idea
for investment art.  Is this true?

Regards  Sandy

It is not really a bad thing, just unnecessary for most varnished oil paintings. I have never heard of an oil painting ‘sweating’ though it might do something similar if it wasn’t completely dry before being put under glass.

Hope that helps.  David

Hi David,

I have been making large oil paintings for a few years now I was previously a printmaker and watercolorist.  However, I have not yet applied a final
varnish to my paintings because I’m not sure of the procedure I should use.
The paintings are mostly on birch panel (a few on masonite), with a few
coats of acrylic gesso ground.  I love the look of watercolour and so have
painted in oils to achieve a similar luminous look – i.e. have saved the
whites I wanted by painting around and rubbing in or wiping off.  As a
result, I have some areas of my paintings that are either totally gesso or
have a small amount of oil paint rubbed in.  Someone once told me that I should apply (spray) a couple of coats of gloss varnish in order to seal the gesso areas and then apply a final layer if I wish a less glossy finish.  However, lately I have been reading about “oiling out” .. so am more confused than ever.  Can you advise me please –
–  Should I use a retouch varnish first, since some of my paintings are 2 or 3 years old?
–  Should I “oil out” to even the look and seal the paint, and if so, what type of oil and how; then how long to wait before final varnish?
–   Should I just follow the procedure recommended above (couple gloss coats then final coat)?

Thanks David, Pauline

Hi Pauline,

I would be interested to know what you are using to thin your oil paint to create those thin layers.  If it is a solvent like mineral spirits or turpentine instead of a good painting medium then you might be better off using acrylics to do those types of paintings.  The oil paint (esp if diluted with solvents) in a thin layer like that will have soaked into the gesso and become part of the ground, just like a watercolour painting is an integral part of the support (paper).  As such, future restoration of the work is very difficult. It is good that you have painted on a rigid support like masonite because such thin layers of oil with most of the binder stripped away or soaked into the gesso is very prone to cracking.

I would not add pure oil to the painting by ‘oiling out’, nor would I apply picture varnish or retouch varnish to seal the painting.  Pure oil will darken and yellow with age, and varnishes are solvent based and are made to be removable, not a permanent part of a painting.  The best solution would be to ‘seal’ the painting with a good quality Alkyd medium like Winsor&Newton’s Liquin or M. Graham’s Alkyd Medium.  Then apply a coat of final picture varnish using a mixture of gloss and matte to achieve the level of desired gloss.  I recommend Liquitex Soluvar varnish that you can mix yourself and apply with a brush.  I would wait a least a month after putting on the medium before applying the picture varnish.

Good luck, David

Hi David … thank you very very much.  I’ve been worrying about this for
about a year or more and it is great to have someone in the know offer a
suggestion.  I have been thinking of switching to acrylics, but find them
hard to work with and not as rich looking as oils, so I will either have to
follow your recommendation to seal and topcoat every time, or get used to
working with acrylics.  I should mention that I try not to use too much
solvent, but rather put a bunch of paint on and then take it off – so it
does soak in.  On the few occasions I’ve used solvent (which gives a really
nice watercolour wash look) I noticed particles of pigment just sitting
there – did not look good from a “permanence” perspective.  I build a pine frame around the back, fill with wood filler, sand, gesso a few times before painting – so I would hate for anything to do wrong at this point.

Pauline

You are right, it is a much better idea from a permanence perspective to wipe off the paint rather than strip away too much of the binder (oil) using solvents.  And acrylics would not work well for that type of painting.

Glad I could help out, good luck and have fun painting.  Ciao, David

Hello David,
I don’t imagine you remember another face from all your students, but I took part 1 of your acrylics last winter at through the Federation. I’ve decided to take you up on your offer to email and request help!

My problem is varnish. I have reread your Retouch Varnish column in the March/April 2004 Art Avenues, but it doesn’t cover my question.  I moved from pastels on mat board to oils on canvas last year. My technique is to blend and feather all color transitions into seamless blends so there are no visible brushstrokes. A body of work had dried down for 6 months, in time for a show that is currently hanging in the Gallery. I hounded oil painter friends and Opus and Loomis worker bees to death about what varnish products to use and how to use them. (I should have just asked you in the first place, hindsight.) I understand the difference between the old resin based types that can yellow down and are difficult to remove, and the newer synthetic types that can be removed with solvent. Not knowing how to apply the brush on type without visible brushstrokes on the oil paint, I opted to try Winsor & Newton matte spray varnish. The result was as dull as the oil paint surface, so I then tried Winsor & Newton satin spray and coated the rest of the canvases with approximately 3 coats each. I began at the top left of the canvas and swept left to right, the way my husband would spray a house. The finish on the satin spray still came out matte and there is no sparkle to the paintings. It is too late to do anything until the unsold items come back home at the show’s end.   However, there is one glaring overspray on the center canvas of a triptych. It is on the top left corner where the sprayer first makes contact, and it has left a darkened blotch. Although it is more likely the gallery owner and I cringe and the public may overlook it, it is annoying the hell out of me. Just before leaving home for the opening, the gallery owner asked me to try to clean it up, so before the opening, I took a jar of clean odorless mineral spirits and a clean white cotton cloth, and tried a gentle circular motion to remove the overspray. But with very little rubbing on my part, paint began to lift, so I immediately stopped. The overspray mark is still visible.  So, I have two questions. 1. Do you know how I can remove the overspray mark? 2. I like oils where the colors are almost shiny and sing. How can I achieve that effect, and with what kind of varnish, and without leaving visible application marks? (Or is my blending technique going to prohibit getting zing in the colors?). Any help would be greatly appreciated.  Thanks very much,

Hi, yes I do remember you.  It is hard to put a face to a name sometimes.

I checked out your website so I would have an idea of what you are talking about.  Cool stuff.  But there are a lot of issues here for sure.  You say you want your oils to have ‘zing’.  Pastels have zing because they are almost pure pigment.  Oil colors will be vibrant too if you use pure pigment colors and do a minimum of blending of hues.  As for the clear shinny effect with oils, that can be achieved by using an appropriate medium.  For now I won’t go into the details of making your own mediums but a good one like Winsor & Newton’s Liquin will help.  Mixed with your paints it will produce a more shiny, transparent effect.  Then use a mostly gloss picture varnish.  I use Liquitex Soluvar or Golden MSA and mix the matte and gloss myself to get a sheen that is just right, usually 4-1, gloss to matte.  You can also try spraying the gloss varnish that you have and then lightly dusting it with a spray of the satin just to take some of the glare away.  Or, as in the case of your satin spray (3 coats!!) a thin coat of gloss sprayed over top should bring up the shine.  But remember, varnish will not make you colors sing, it will only make the surface more or less shiny.

Remember too, that final picture varnish is supposed to be a temporary layer that can be removed.  So it should not be thick.  You should be able to apply a good varnish like the two I mentioned above with a brush without leaving application marks.  Make sure you use a good quality soft brush and add a little extra thinner for finer applications if necessary.  Then, brush over it lightly with the unloaded brush at the end to create a smooth even surface.  Spraying is always an easier way to apply a thin smooth application however.  So, one thin coat of picture varnish is all that is needed to protect your painting.  Three coats is not necessary and will make it hard to remove if the painting should need restoration at some point in the future.

As for the blotch, it sounds to me like the paint was not completely dry before the varnish was applied.  That is why some came off with the solvent.  If a painted area is not completely dry it may darken when a varnish is applied as it softens the paint and ‘sinks in.”  You will have to wait a while before you try again, I can’t really say how I would approach the problem after that without getting my hands on it.  Hope that helps, let me know if you have other Q’s or need some clarification.  Bye for now.  David

Hi David,

Wow, love your details! I’ve printed your reply and will be practicing on some little items I prepared for testing on. Thank you very much for your thorough reply. Based on your reply, I’ve got one more question.  And I must say, your info from the acrylic course has been immensely helpful in my approach to oils (not a paradox, I assure you), regarding purity of pigment and ‘not to dos’ in mixing, etc. I’ve switched from cheapolas to pure and expensive with my paints and the difference has been stunning.  To warp a Monty Python quote, “I’ve learned oil painting from a book.” You mention using WN’s Liquin as a medium. I have been using 1 part linseed to 4 parts odorless mineral spirits. I prefer to work in opaque colors and not have any transparency. What medium would be best to retain opacity?

Ok , you do understand that opaque colors means no shine, right?  You can of course still have the vibrant colors if you follow the ‘light rules’ I discussed in the workshop (see article on FCA website entitled “Light Rules”) but luster and shine come from using transparent colors and a glazing medium.  Painters wanting a non reflective surface in oils  use a bee’s wax medium.  It is slow drying compared to the Liquin but makes the colors matte and quite nice and buttery to work with.  Check it out at the art supply store.  Using a simple mixture of linseed oil and solvent like you use is a no-no for permanent painting techniques and may explain why your painting is not drying properly. You are just increasing the amount of oil in the paint, and it already has more than it needs in most cases.  the oil in the paint is a necessary evil, it causes the paint to dry slow, wrinkle, yellow and darken with age, so you definitely don’t want the add extra! Get a good quality commercial medium from a high end company like W&N or Gamblin.  I wrote an article for the magazine in July/Aug 01 about oil painting mediums and good recipes to make your own.  I have attached a copy.  I will be teaching an oil painting workshop for the FCA in the spring that will have all of the usual techno stuff we have come to expect from me…  bye for now, D

The following is an exchange that raises a couple of common concerns for oil painters:

Dear David,

I have many old oil paintings over which I would like to begin new oil paintings. I prefer to start with an all-white canvas. Is it OK to paint over the old painting with an oil-based alkyd ground?

Thanks for your attention to my request, Louise

Hi Louise,

I have a question for you.  Have you found any oil/alkyd ground for artists?  I would like to know if there is any other source cuz I have only found one so far.  As for your question, it is an ok idea but not a great one if you are concerned about permanence.  Oil paintings that are simple, relatively thin layers painted over a flexible ground/primer (like the oil modified alkyd primer you mention), and preferably on a rigid support, or linen, have the best chance of avoiding cracking or flaking as they age.  The different layers that you are proposing, however, primer/paint/primer/paint, may not be as stable.

As well as questionable adhesion of the new painting on the already used canvas, there is the concern of the old painting showing through.
All colors are transparent in varying degrees and oil paint becomes more transparent with age (and darker and more brownish in hue) so your new painting would get darker with age as the first painting shows thru more and more.  This phenomenon is called ‘pentimento’ and it can be seen in old paintings where the artist painted a subject on top of an already painted background thinking they would be covering it up.  Also, the brush strokes and texture of the old painting may interrupt the new picture’s surface.

Having said all that, here is the best way to go about it to minimize later troubles:

1.  Scrape off as much of the old paint strokes and impasto as you can with a palette knife.  Use a flexible razor or blade to remove as much of the old paint as possible without scraping the ground itself.  You may need to place a board under the canvas to keep it from sagging while you scrape.

2.  Rough up the surface with sandpaper to give it ‘tooth’ so the next layer will adhere better.

3.  Dust (vacuum) the surface and wipe it clean with a solvent like turpentine or mineral spirits.

4.  Apply a thin coat of white or light gray paint, or primer.

It is very important to remember that when you are scraping, sanding and cleaning the surface, that pigment particles that are potentially highly toxic will be stirred and you must contain these and not breath them.  I recommend using a vacuum cleaner and dust mask.

hope that helps Louise.  cheers, david

Hi David,

Thanks a lot for your reply. Perhaps I should not have called the alkyd primer “oil based.” What I have is “Beauti-Tone Alkyd Primer Sealer Undercoat” from Home Hardware. It is cleaned with mineral spirits.

Alkyd appears to be a major ingredient in many oil paint mediums, but using the primer mentioned above over old oil paintings does not follow the rule of ‘fat over lean.’ Perhaps this doesn’t matter, if the old paintings are thoroughly dry and the primer is considered like a glaze. What do you think?

Also, what about using Gamblin Ground instead? It too is alkyd-based. The bottom line is that I’m just trying to get the canvases back to ‘white,’ without the expense of using oil paint from the tube.

Thanks again, Louise

Hi Louise,

You are right, the fat over lean rule only applies to undry layers of paint.  The rule also says it is not good to put a brittle layer on top of a more flexible layer, you can imagine what would happen.  But the alkyd primer is quite flexible.

As for the alkyd sealer undercoat from Home Hardware I would not advise that you use it if you want your paintings to last.  These commercial products are not made with permanence in mind and usually contain several ingredients that may have unpredictable results when used in conjunction with artist’s materials. In the case of painting over old canvases, however, permanence is not usually a primary concern and you may want to go ahead and try the commercial primer.  The Gamblin alkyd primer is a good product but it is expensive too, about $80 Canadian a quart! – but that will go a long way…  hope that helps, bye for now, David

David,

I’ve just started to paint with water-miscible oils having been away from oils for many years. There is little information available about permanency. In various articles, curators have raised this question but the jury seems to still be out on this subject. What’s your opinion? >In addition, although I had a lengthy discussion with a p.r. rep from Grumbacher who uses them, her method seems very contrived. She mixes all her colours with the ‘special’ linseed oil and quick dryer before going out to paint in situ. This, of course assumes that you know how much of each colour you are going to use and adding the quick dry before using the paint means that anything left over is going to become unusable before you may be able to return to your subject to repeat the same light conditions. > >Then, there is the question of fat over lean. If I use water to dilute the mixture for blocking in, there seems to be a question that if there is too much water, adhesion to the surface will be in question. >I’m also finding colour blending to be quite different from traditional oils. >Perhaps I need to just stick at it to discover my own blends but there is this nagging question: Is the toughing out worth it? Will the paint just crack off the canvas in a few years if I produce something with promise? >If you have some thoughts on this subject, I would be appreciative if you could take a few minutes to answer. > >Sincerely, Marilyn

Hi Marilyn, that is a really good question. I have been curious about water-miscible oil paints since I first heard of them some 20 years ago but I have never really looked into it.
There is actually a long history (I’m talking centuries) of water mixed with oil paints to form an emulsion paint. But these methods fell out of favor after the development of oil painting reached its heights during the Renaissance. frankly, unless these paints offer something more than the simple conveniece of being able to use water instead of solvents, then I don’t see the point. Still, this seems to be the main reason that they are being marketed: for people who want the blending qualities of oils without having to deal with solvents. Some people are allergic to turpentine in particular.
what interests me most is the issue that you brought up about them having different working qualities compared to regular oils. when good quality oil paints are used with good painting mediums they can create effects that are unrivaled by any other medium. you mention that they don’t blend the same. The buttery smooth texture would naturally be altered with the addition of water. the manufacturers have no doubt added some agent that acts an emulsifier. then, as you say, what happens to the paint film when the water evaporates, and the water underneath? Here is a quote from a chemist at Winsor & Newton, who make Artisan water-mixable oil paints:
Artisan is based on linseed oil, which has been modified to make it water-mixable if required; otherwise it behaves like a normal oil. There is no chemical reason to suspect the modified oil is any less stable than regular oil. Emulsified oils, in fact, have a history of stability going back to prehistoric times. The current water-mixable oils have been around for over 20 years. Developments in acrylics have pushed them into the background, but market requirements for less hazardous materials have brought them to the fore again.”

A conservator at the Canadian Conservation Institute adds: As Alun (the chemist) says, there’s no reason to suspect that the Artisan vehicle will behave any differently than a conventional oil during oxidation (drying).

So I would say to you, Marilyn, wait for the underpainting to be thoroughly dry before overpainting, just like you would for normal oil painting. It then comes down to a question of how well they behave for the type of paintng you want to do. I know that there is at least one book out there written about painting with water-mixable oils. Do a title search at Chapters or Amazon and you will come across it. It may be the best source for telling you how to get the most out of these paints. otherwise, if anyone else out there has some experience and info to share about water-mixable oils, please drop me a line.

thanks for the question Marilyn.

Hi David,

I have a question about oil painting without the use of solvents. My main interest is portraiture and I paint in oils, adding oil almost exclusively as my medium. I started doing this because of health concerns and the necessity of working in places with inadequate ventilation and find I like the results. I can’t stand the smell of turps, so I sometimes use a citrus-based solvent for the first priming or underpainting layers (or occasionally acrylics). I buy high quality oil paints and observe the ‘fat over lean’ principle as I build successive layers. I often use several layers of very thin glazes made exclusively by adding oil to the paint as I reach the end of the process. I do understand that oil will yellow over time. Apart from that, will this technique cause problems with my paintings down the road? I want my work to last and my clients to be happy. I’m using various types of linseed oil. Are there others that would be better? Or any recommendations for glazing mediums that are safe?

Thank you very much! Jennifer

Hi Jennifer,

Using linseed oil, or any kind of oil as a painting medium will cause yellowing.  Oil paints will yellow and become darker over time even without the added oil, adding more only compounds this result.  Also, extra oil will cause wrinkling as well as slow and erratic drying of the layers.

It would be best to paint without adding any extra oil at all.

There are a couple of companies making excellent, solvent free painting mediums that you should consider.  Compared to using linseed oil, a superior painting medium will give your glazes luster and transparency.  The paint will be smooth and easier to brush and it will also help regulate the drying time of the various colours (pigments).  Your paintings will be more fun to execute, they will look better and stay that way longer.

Hope this helps.  All the best , David

Hi David,

A further question about the painting mediums:  Do I blend this with linseed oil as one would use turps throughout the entire process, with more medium in the under layers and more oil later?  Or do you use it alone for glazing? (that is on top of oil layers?)

Thanks, Jennifer

Jennifer,

Use ONLY the painting medium to dilute your colors (and the
occasional dab of solvent, esp. in the underlayers) – NEVER
ADD LINSEED OIL (or any other kind of oil) TO YOUR PAINT – NEVER!!!!!

I have read and heard about the advice to add oil to successive layers of paint to accommodate the widely misunderstood notion of ‘fat over lean’ – it reflects a fundamental misunderstanding of the nature of oils paints – they already contain too much oil!!!

I wrote an article I wrote a couple of years ago on the fat over lean issue and you can find it on my website.

Take your linseed oil and use it to polish antique furniture!

Hi David

Thanks for your answer….. I have to say: YIKES!  I’m totally blown away.  I am pretty much self-taught. I’ve taken a couple of painting classes and I’ve never heard this before, just been told to use more solvent/turps in the early layers and more oil in the later layers.   In fact, a very well known artist (who I won’t name) told me I was “just fine” to use oil and nothing else as long as I observed the fat over lean principle (less – more).  I wasn’t totally comfortable about it, so recently I’ve started underpainting in acrylics so I could use less oil.  I’ve been merrily painting like this and sold paintings, but always wondered……. One of my concerns with this new method is that everything will dry too quickly.  I like to take my time and paint more into areas that aren’t totally dry a few days later.  In fact I’ve been advised by one academy trained teacher to “oil out” prior work before painting over it – that is to rub it with a tiny bit of oil to help the new paint adhere.  The main reasons I don’t use acrylics is they dry too fast and the colours always seem to change.  I will try your method using this new medium only.  Should I be adding more and more as I make more layers?

Also, what did oil painters do before the invention of alkyd mediums?  I thought linseed oil had been used for centuries? I really appreciate that you have taken the time to help me with this.

Many thanks, Jennifer

Hello again Jennifer,

many well known painters over the last couple of centuries have made the kind of erroneous technical assumptions that you mention, it is not their fault, no one was there to tell them different and after the master/apprentice system dissolved in the 18th century very little of the scientific information about painting materials and techniques was passed on in written form…  I had to spend years researching to learn it all myself…

If you know the various drying times of the different pigments and layer them accordingly you will not have any problems, that is, fast dryers under slow dryers.  You don’t need to add more of anything (including the medium, and ESP NOT MORE OIL!) to accommodate the ‘fat over lean’ principle.  Thin layers of faster drying paint, with a SMALL amount of added solvent to help, is a good idea in the underpainting.  Then just proceed to paint on successive layers adding the medium when you want a more transparent effect.

For centuries painters avoided oils or looked for ways to make them dry faster by adding resins, you actually WANT them to dry slow!  Being able to return a few days later to muck around in the still wet paint is unusual.  Adding extra oil will definitely slow down the drying time enough for you to do this however.  There have been great artists who have wanted to do the same thing as you, Da Vinci is perhaps the most famous.  He wanted a slow drying paint so he could play with the blending, you know, the ‘sfumato’ technique that he made famous.  But he knew enough not to add more pure oil to his paint.  Instead, he ground his paints in walnut oil instead of the more popular linseed oil, which dries much faster than walnut.  The only company making walnut oil paints today is M. Graham.

There are two other options that you should consider.  Some companies make both fast and slow drying mediums that you can add to your paint.  Nothing will retard the drying time as much as straight oil but of course you don’t want to keep adding that to your paint…

The academy trained teachers suggestion of ‘oiling out’ can be modified.  Many painters, including me, return to their paintings days or even weeks later and start the new painting session by first applying a transparent glaze, that is a combination of a color and a high quality painting medium, and then painting into the wet glaze.  The idea is the same only we are substituting the medium for the oil.  Adding a pigment (colour) to the glaze instead gives the mixture added stability.  Rembrandt would labor away at his paintings for months and often put them aside for weeks at a time.  When he returned to them he would invariably apply a dark glaze, usually brown, black or blue, over the whole piece, wipe some it off and then start painting ala prima into the still we glaze.

There are a couple more articles on my website
(davidlangevin.com) that may give you some more insight and information on these matters.

Cheers, David

  1. Guidelines for Permanent Painting in Oils
  2. Paint on a good quality ground (gesso) that is thick enough to prevent oil seeping through to the support.
  3. Paint on a rigid rather than a flexible support whenever possible (see #19).
  4. Paint fast dryers under slow dryers.
  5. Paint ‘lean’ (low oil content) pigments under ‘fat’ (high oil content) ones.
  6. When painting in layers keep the under layers thinner and leaner.
  7. Paint oils over acrylics if you must but not the other way around.
  8. Do not paint over a layer that has a dry skin but is soft and wet underneath.
  9. Oil paint can be thinned with only small very amounts of solvent.
  10. Do not add extra oil to your paint.
  11. Use a good painting medium to thin paint and make glazes and veils.
  12. Use Retouch varnish sparingly.
  13. Keep the underpainting light and bright (see # 17&18).
  14. Do not apply the paint too thick.
  15. Heavy texture and collage effects are best done with acrylic paints and mediums.
  16. Do not use old paint that has begun to dry and is stiff and rubbery, it will not adhere well.
  17. Paint around things rather than over top unless you want the underpainting to show (see # 17&18).
  18. Remember that oil paint darkens and becomes more yellow/brown with age.
  19. Remember that oil paint becomes more transparent with age.
  20. Remember that oil paint becomes more hard and brittle with age.
  21. Use soap to clean hands and brushes, not solvents.
  22. Wait between 3-12 months before applying picture varnish, depending on the thickness of the paint.
  23. Do not hang or store oil paintings where they will be exposed to humidity or large temperature fluctuations.
  24. Never use water to clean an oil painting.
  25. Use the best quality paints you can afford.
  26. Do not mix low grade and professional grade paints in the same painting.
Hi David,

I have a binder with all your articles but on review today I found no answer to my thoughts about inserting various collage media into an oil painting.  I have a thin layer of dry oil onto which I would like to attach a paper drawing. Would an Alkyd medium be the way to go?  Both under & over? What about if the piece was covered with acrylic, or if it is a piece of canvas?

Thank you for sharing your knowledge over the years, Marlene

Hi Marlene,

In general it is always precarious to mix oils and acrylic paints and mediums when you are concerned about permanence.  First, acrylics do not stick well to oils at all, so I would say you should attach your paper to the oil painting with an alkyd medium as you suggest.  Better still, do all the collage work in acrylics, using gel mediums to attach the paper/fabric on a rigid support and then put your oil painting layers on top of that.  Oils stick better to acrylics and on a rigid surface there is much less chance that they will separate.

Your case also brings up a different concern, that is the difficulty of collage elements with oils.  Oil paints dry thru a complicated process of oxidation and adding various mediums and other elements that may disrupt that process will lead to unpredictable results.  Moreover, oils are very acidic and so paper and fabric products will be adversely affecting by coming into direct contact with it.  The oil from the paint is readily absorbed by these products causing them to yellow and deteriorate very quickly.  Once these surfaces have depleted much of the oil from the paint layers, making them ‘lean’, they are now much more brittle and susceptible to cracking and flaking.

So, as a general rule, collage elements and oils do not mix well for permanent painting.  Acrylic underpaintings with collage elements done on a rigid support, that are painted over in oils, or better still acrylics, are much more stable.

Hope that helps, cheers, D
Hi David,

Thanks for your reply, your information and your support of my art.  I will try the alkyd, maybe incasing it fully before inserting it on the oil base. With a bit of wax added to the mix it might not get brittle.  I am still getting a grip on which colors are fat & which are lean but have also realized that the brand of oils that I bought on sale are very oily.  I read once about squeezing these kind of oils onto a cardboard palette & I will try that today.

I look forward to your next article, Marlene

Hi Marlene,

A practice that I used to help familiarize myself with the drying rates of the different pigments in oils was to paint out a swatch of medium thickness of each color, and brand,  on a gessoed canvas and then check it twice a day and mark the drying time under each one.  It is important to note the time in the drying when the paint is dry to the touch but still soft under the skin – this is the worst time to paint over them as the layer is actually expanding.

Modern oil paints, esp. inexpensive ones, suffer from too much oil content as it is.  The ‘Old Masters’ mixed resins into their paints to make them more stable and faster drying.  A practice that I do is to first squeeze them out onto an absorbent paper towel to allow some of the oil to be removed, then I will replace the oil by adding a little alkyd medium before starting to paint with it, effective creating a resin/oil blend in my colors.

Have fun painting!  David

OIL ON OIL

Hi David,

I have a question about oil painting without the use of solvents.

My main interest is portraiture and I paint in oils, adding oil almost exclusively as my medium.  I started doing this because of health concerns and the necessity of working in places with inadequate ventilation and find I like the results.  I can’t stand the smell of turps, so I sometimes use a citrus-based solvent for the first priming or underpainting layers (or occasionally acrylics). I buy

high quality oil paints and observe the ‘fat over lean’ principle as I build successive layers.  I often use several layers of very thin glazes made exclusively by adding oil to the paint as I reach the end of the process. I do understand that oil will yellow over time. Apart from that, will this technique cause problems with my paintings down the road?  I want my work to last and my clients to be happy.   I’m using various types of linseed oil.  Are there others that would be better?  Or any recommendations for glazing mediums that are safe?

Thank you very much! Jennifer

Hi Jennifer,

Using linseed oil, or any kind of oil as a painting medium will cause yellowing.  Oil paints will yellow and become darker over time even without the added oil, adding more only compounds this result.  Also, extra oil will cause wrinkling as well as slow and erratic drying of the layers.

It would be best to paint without adding any extra oil at all.

There are a couple of companies making excellent, solvent free painting mediums that you should consider.  Compared to using linseed oil, a superior painting medium will give your glazes luster and transparency.  The paint will be smooth and easier to brush and it will also help regulate the drying time of the various colours (pigments).  Your paintings will be more fun to execute, they will look better and stay that way longer.

Hope this helps.  All the best , David

 

Hi David,

A further question about the painting mediums:  Do I blend this with linseed oil as one would use turps throughout the entire process, with more medium in the under layers and more oil later?  Or do you use it alone for glazing? (that is on top of oil layers?)

Thanks, Jennifer

Jennifer,

Use ONLY the painting medium to dilute your colors (and the

occasional dab of solvent, esp. in the underlayers) – NEVER

ADD LINSEED OIL (or any other kind of oil) TO YOUR PAINT – NEVER!!!!!

I have read and heard about the advice to add oil to successive layers of paint to accommodate the widely misunderstood notion of ‘fat over lean’ – it reflects a fundamental misunderstanding of the nature of oils paints – they already contain too much oil!!!

I wrote an article I wrote a couple of years ago on the fat over lean issue and you can find it on my website.

Take your linseed oil and use it to polish antique furniture!

 

Hi David

Thanks for your answer….. I have to say: YIKES!  I’m

totally blown away.  I am pretty much self-taught. I’ve taken a couple of painting classes and I’ve never heard this before, just been told to use more solvent/turps in the early layers and more oil in the later layers.   In fact, a very well known artist (who I won’t name) told me I was “just fine” to use oil and nothing else as long as I observed the fat over lean principle (less – more).  I wasn’t totally comfortable about it, so recently I’ve started underpainting in acrylics so I could use less oil.  I’ve been merrily painting like this and sold paintings, but always wondered……. One of my concerns with this new method is that everything will dry too quickly.  I like to take my time and paint more into areas that aren’t totally dry a few days later.  In fact I’ve been advised by one academy trained teacher to “oil out” prior work before painting over it – that is to rub it with a tiny bit of oil to help the new paint adhere.  The main reasons I don’t use acrylics is they dry too fast and the colours always seem to change.  I will try your method using this new medium only.  Should I be adding more and more as I make more layers?

Also, what did oil painters do before the invention of alkyd mediums?  I thought linseed oil had been used for centuries? I really appreciate that you have taken the time to help me with this.

Many thanks, Jennifer

Hello again Jennifer,

many well known painters over the last couple of centuries have made the kind of erroneous technical assumptions that you mention, it is not their fault, no one was there to tell them different and after the master/apprentice system dissolved in the 18th century very little of the scientific information about painting materials and techniques was passed on in written form…  I had to spend years researching to learn it all myself…

If you know the various drying times of the different pigments and layer them accordingly you will not have any problems, that is, fast dryers under slow dryers.  You don’t need to add more of anything (including the medium, and ESP NOT MORE OIL!) to accommodate the ‘fat over lean’ principle.  Thin layers of faster drying paint, with a SMALL amount of added solvent to help, is a good idea in the underpainting.  Then just proceed to paint on successive layers adding the medium when you want a more transparent effect.

For centuries painters avoided oils or looked for ways to make them dry faster by adding resins, you actually WANT them to dry slow!  Being able to return a few days later to muck around in the still wet paint is unusual.  Adding extra oil will definitely slow down the drying time enough for you to do this however.  There have been great artists who have wanted to do the same thing as you, Da Vinci is perhaps the most famous.  He wanted a slow drying paint so he could play with the blending, you know, the ‘sfumato’ technique that he made famous.  But he knew enough not to add more pure oil to his paint.  Instead, he ground his paints in walnut oil instead of the more popular linseed oil, which dries much faster than walnut.  The only company making walnut oil paints today is M. Graham.

There are two other options that you should consider.  Some companies make both fast and slow drying mediums that you can add to your paint.  Nothing will retard the drying time as much as straight oil but of course you don’t want to keep adding that to your paint…

The academy trained teachers suggestion of ‘oiling out’ can be modified.  Many painters, including me, return to their paintings days or even weeks later and start the new painting session by first applying a transparent glaze, that is a combination of a color and a high quality painting medium, and then painting into the wet glaze.  The idea is the same only we are substituting the medium for the oil.  Adding a pigment (colour) to the glaze instead gives the mixture added stability.  Rembrandt would labor away at his paintings for months and often put them aside for weeks at a time.  When he returned to them he would invariably apply a dark glaze, usually brown, black or blue, over the whole piece, wipe some it off and then start painting ala prima into the still we glaze.

There are a couple more articles on my website

(davidlangevin.com) that may give you some more insight and information on these matters.

Cheers, David

 

 

 

 

 

Hello David,

Is it worthwhile to apply lead white oil ground to a sized hardboard (masonite), or would it be better to use the lead ground on canvas? I do have some spare boards available, but didn’t know if the end product is good, or as good as the quality of canvas w/lead ground.  And what drying time would I allow between the lead ground coats on hardboard?  And what drying time would I allow between the lead ground coats on canvas?  Should I size the back side of the hardboard as well?

Thanks!  Sara

Hi Sara,

I would use acrylic gesso on the hardboard and save the lead white ground for the canvas, and you don’t need to size the back of the panel, though it may help to keep it from warping too much.  If you find the acrylic gesso too absorbent for the oil paint you can apply a size layer or “Imprimatura”, made of alkyd medium and some color.

Wait a day or two before applying a second coat of lead primer on the canvas.  Make sure that your canvas is properly sized before you apply the oil primer though, use a PVA primer, Golden’s GAC 100 medium, or good even good old fashioned animal hide glue (Rabbit Skin Glue) if you must, otherwise the oil paint will ‘eat’ your canvas (cause it to rot and break down) in a few short years.

Have fun!  David

As I mentioned in a previous article, and it is worth repeating, the Golden Acrylics company has formulated special mediums (GAC 100 and GAC 400) that are ideal for preparing cotton canvas for oil paintings.  You can even modify an already primed canvas to create a very durable painting surface for oils.  No more need to use the traditional linen canvas with Rabbit Skin Glue Size and Lead White Ground.  Read on.

 

Hi David,

I Just read your article regarding preparing canvases for oils and wanted to be sure that I understand fully before applying the Golden GAC 100 & 400 to my canvas as I just purchased a large canvas that I don’t want to ruin…and I use regular oil paint, not water soluable.

The canvas is pre-gessoed by Classic Gallery.  So my understanding is that I apply GAC 400 direct to the back of the canvas to stiffen it.  Do I use it straight from the bottle or thin it a little?  Then I coat the front of the canvas (over the initial gesso) with two coats of GAC 100, then I re-gesso.  Is this good?

Sandy

That is correct Sandy, and yes you can add a little water, up to about 20% by volume, to the GAC mediums if you like.

 

Oil Questions

Q:  I made the mistake of mixing a veil instead of a glaze by using white to try for the greyish tones;  I have tried subsequently and unsuccessfully to undo the damage; I can’t seem to match the colours without white, and adding white seems to have be my downfall; any suggestions?  Is it ‘too late’ to undo the ‘veil’ effect?

A:  I am not sure exactly what effect you are trying to achieve, but a typical painting procedure would be to let the veil dry and paint over it with a glaze.  Veils are most often glazed over as their main function is to create a lighter underpainting for another glaze.

Q:  How long would you suggest I wait before applying the glaze over the underpainting (veil)? I realize it depends on how thick the paint is; it’s not very thick, but was applied ‘tube strength’.

A:  You can paint over a dried underpainting when the layer is dry to the touch, but not if it has formed a ‘skin’ and is still soft underneath.  It is at this time that the oil paint is absorbing the most amount of oxygen for polymerization and the layer is actually expanding.  This skin usually forms between the 2nd and 3rd week of drying in a layer of normal thickness.  Putting a fast drying glaze over an expanding underpainting (dry to the touch and soft underneath) would lead to cracking and lifting of the glaze layer and would upset the polymerization of the under layer by cutting off oxygen.

 

You say the paint was applied ‘tube strength’ so I assume there were no mediums added to accelerate/regulate drying.  As you know different colors (pigments) dry at varying rates in oils and one of the reasons for adding mediums, like a good quality alkyd medium, is to speed up and also regulate drying times.  By ‘regulate’ I mean that the addition of an alkyd medium will help the different colours dry at approximately the same speed.  Over a thin underpainting with medium added I can often glaze over it within a couple of days or even a few hours, for thicker layers, especially if no medium is added, it may take up to a month.

 

Of course, in my underpaintings I invariably use lean, quick drying colors.

Lead, or Flake white is invaluable for this purpose.  Now some manufacturers are producing a ‘foundation’ white instead of offering the traditional lead white formula.  This new replacement has the addition of an alkyd medium to speed up drying time.

Q:  Is there a reason for using Galkyd Slow Dry instead of just Walnut Oil to slow the drying time of the paint?  Would the ratio be one to one for whatever colour I use?

A:  Modern tube oil colours already have too much oil in them.  Adding extra oil, even Walnut oil, to your paint will indeed slow the drying time but will affect the drying rates in erratic ways and will eventually cause wrinkling and cracking in some areas.  The colours will also eventually yellow more.  Most manufacturers make slow drying mediums.

The ratio of medium to paint varies depending on the level of transparency required and the relative tinting strength of the pigment you are working with.  There is no standard ratio.  A good guideline is to use as much medium as is required to achieve the desired effect, but no more.

Q:  I have opened up my Paynes Grey, and also my Cad red, and oil oozes out of them; I watched Yvonne Reddick squeeze her paint onto a paper towel to absorb some of the excess oil.  Should I be storing my tubes of paint vertically or horizontally?  Does one or the other preserve the paint better, or does it matter?  Should one pour off the excess oil before squeezing out the colour?

 

A:  Sometimes oil will rise to the top of the tube if it has been sitting for a long time.  It doesn’t matter how you store your tubes but I prefer to let the pigment settle and remove the excess oil.  You don’t want to use that oil because indeed modern tube oil paints already suffer from an excess of oil.  It is a good practice to squeeze out your paints onto a paper towel to absorb some of the extra oil. You can then replace it with a good quality alkyd medium.  By doing this you are effectively creating a resin/oil paint like the ones used for centuries before the introduction of tube oil paints.


OILS OVER ACRYLICS

Hi David,

What do you think of using acrylics for underpainting, followed by oil
paints on top?  I know many artists who do this, including some who teach at
reputable art schools.   But I¹ve heard totally conflicting views on whether
it is ‘safe’ in terms of permanence and archival quality.  Recently the
technical rep for Winsor & Newton told me the oils could eventually peel
or flake off.  But I¹ve never heard of this happening.  I think it is safe to
paint oil over latex on a wall, but of course no one expects that to last
hundreds of years.   It seems the gesso ground on pre-prepared canvases
may be acrylic anyway.

I prefer oils because of the range of effects possible, because I like the
slow drying time, and the ability to work wet in wet.  But it would be great
to be able to cover large underpainted areas with a fast drying acrylic to
get a jump on things.

I also think it would be particularly interesting to be able to use oil
glazes on top of acrylic metallic or interference colors.

Your thoughts would be appreciated!
Many thanks, Jennifer

Hi Jennifer,

It is not uncommon of artists to paint oils over acrylics and the practice of applying oils over a water based media dates back hundreds of years.  Oils were often painted over egg tempera underpaintings, even before the Renaissance.

Still, there are some issues that need to be addressed if you are concerned about permanence.  Oils do stick better to acrylics than the other way around, that is for sure, but there is a danger of them not adhering to each other permanently if certain conditions are not met.  Yes, the modern gesso we use to prepare our canvases is acrylic but it is a ground, not paint.  That means that it is much less flexible and more absorbent than acrylic paint.  The oil paint can adhere much better to it for these reasons.

The problem arises when oils are painted over acrylics on a flexible support, like canvas, the early Renaissance painters only painted oils over a tempera underpainting on board.  Acrylics will remain flexible indefinitely, oils become harder and stiffer with age.  As the canvas flexes and moves over time with temperature and humidity fluctuations, the acrylic paint will move with it, and the oil paint will have a much harder time doing that as it ages.  That is when the cracking and peeling will begin as the bond between the rigid oil paints and the flexible acrylics is compromised.  Imagine, as a more exaggerated example, stretching a plastic bag that has a film of dried oil paint on it.

So, the safest way to paint oils over acrylics is, of course, to paint on a rigid support like hardboard.  If you still perfer to paint on canvas you can minimize the risks by preparing your canvases in the manner I recommend in previous articles I have written on the subject; they are posted on my website:  http://davidlangevin.com/technicalqanda/7.html

Have fun!  D

Hi David,

I appreciate reading your articles in the FCA Art Avenue, therefore when faced with the drying time issue of some black oil paint, I thought I would pop you a note.

 

I completed a large piece that I must have dry and varnished for a gallery demonstration painting and exhibition in a month.  There is a small patch of black oil on this piece that has remained tacky, and still comes off on my finger after having finished painting it a month ago.  Temperatures have been cold with a high humidity due to so much rain.  I put a space heater on for a few minutes ever so often thinking that perhaps it needs some warm dry air.

 

I used M. Graham Lamp Black oil color.  I had applied a very thin bit of walnut oil first because I was painting effects into this background which I wanted to have soft & disappearing edges.  The other colors which I applied have dried, however the black still wipes off.  What are the chances of it drying soon enough to apply retouching varnish and present?  Is there something I can do?

 

Rena

 

Hi Rena,

Certainly warm dry air helps to dry oil paint but it is not acrylic so that will not really accelerate the polymerization/oxidation process of oil paint enough to help you with this situation.  I don’t see any solution except to remove the black and replace it with a faster drying black like Mars, and add some alkyd medium and/or some Cobalt dryer to accelerate the drying process.  This mixture would certainly be at least dry to the touch within a couple of weeks.

I would remove that layer in any case because it is unstable and eventually will cause a yellowing and wrinkling effect of the paint layer.  I have written about the dangers of using extra oil in the painting before.  You can find articles on oil painting techniques in the ‘oils’ section on the ‘technical Q&A’ page of my website.

Moreover, walnut oil is the slowest drying of all the drying oils, that is one of the reasons it was the preferred by Leonardo da Vinci over Poppy and Linseed oils – he like to take his time and work that ‘sfumato’ thing.  M Graham uses walnut oil  to make their paints as you are no doubt are aware.  Adding extra walnut oil underneath the black is a significant factor in your problem, that will slow down the drying time a lot.  Add to that the fact the Lamp black is the ‘fatest’ (high oil content) and slowest drying of all the blacks and it is not a surprise that it is taking so long.

best of luck and let me know what happens.

6 Comments on “Oils”

  1. paul torres

    Hi David ,I would like to ask you that I have run into so many articles that says the best medium is turpentine mixed with stand oil or sunthickened linseed oil but they don’t recommend the use of damar varnish or mastic varnish mixed as a medium, because it will easily be removed as a layer ,so Ive been using oms by gambling for 15 years now and when I have enough ventilation I use turpentine by Winsor Newton mixed with stand oil ,which is even better ,I also use it for oiling out, do you recommend it? any advice I would greatly appreciate it, and thank you for having all this help for Artists this is great.
    Paul

    1. david

      Hi Paul, those articles are wrong. Thinning paints with oil and/or solvent is a very common method and has been taught, and used by many experienced painters for decades. It produces poor results. Go to the ‘technical Q&A’ page on my website, click and ‘oils’ read the articles entitled ‘oil on oil’ and ‘guidelines for permanent painting in oils’. these will explain things for you. check out also: ‘fat over lean’ and ‘daVinci didn’t use oil paints’. all your questions should be answered there. If not, shoot me another email. D

  2. Pamela

    I just found your site and have enjoyed reading it for the last 3 hours!
    thanks for al the time you spend educating others.

    I have a question. I have been painting with oils for 15 years and have used alkyd mediums. I have recently been doing more impastos with glazes and am more concerned than I have had to be previously with the fat over lean principle as I am now using thick under layers. Gamblin is a manufacturer that I like and trust (and it is local for me). I read their recommendations on fast and slow drying mediums. For slow they recommend 30% stand oil and 70% Galkyd; for moderate, 20% poppy oil and 80% Galkyd; for fast 100% Galkyd. Then I read your comments about NOT adding oil to paint. Now I am really confused. Can you please speak to this? Thanks!

    1. david

      I am also a bit confused. Stand oil is partially oxidized oil, and so is faster drying and less prone to the defects of regular oil. There are other ways to slow down drying time without adding extra oil; using M.Graham paints made with Walnut oil, which naturally dries slower than linseed or safflower oils, or adding Lavender oil to the paint.

  3. Heather

    Really appreciate your guidance on preparing canvases for oil painting. I understand the GAC 400 is used to stiffen the canvas but isn’t strictly required. Would you recommend it as a matter of good practice for any canvases (linen or cotton), whether raw or pre-primed with acrylic gesso or some type of oil primer? If the canvas is already on stretcher bars, is it still a good idea to apply the GAC 400?

    For raw linen or cotton canvas, unstretched, I believe you are recommending a coat of GAC 400 first (on the front) to stiffen it somewhat, and then the two coats of GAC 100 (followed by an oil primer of some type)? How long would you recommend waiting after the painting is finished prior to stretching it (assuming the paint isn’t unduly thick)?

    Is it a good idea to apply something on the back of the canvas in any event for protection?

    1. david

      Hello Heather,
      The answer to your first two questions is ‘yes’. I would say the GAC 400 fabric stiffening medium is highly recommended for application on any type of canvas used for oil painting. Dried oil paint does not like to be attached to a flexible surface that moves around. Also, the acrylic medium will make the fabric much less hydroscopic (absorbing atmospheric moisture) which also causes the fabric to flex and loosen as the temperature and humidity in the environment changes. Yes, apply the GAC 400 to the back of the canvas after it is stretched. In fact, the canvas will be easier to stretch without the acrylic medium. But do NOT apply it after it has been painted on in oils. The water in the medium will seep thru the canvas and may disrupt the paint layer.
      A correction to your next inquiry needs to be made. The GAC 100 is for the front of the canvas, acting as a size. The acrylic gesso or oil based primer can then be applied. The GAC 400 fabric stiffener is for the back of the canvas. Do not put it on the front. Yes, the back of the canvas needs to be protected for the reasons outlined above. please email me if I do not respond promptly.

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