Preparing Canvases

[Virgil Elliott]

Tarique,

You have quite a few questions, and I'll try to cover them all without having to write a book here. The advice Mary (I believe it was) gave you about using Fredrix oil-primed linen and stretching it yourself is good. The very best pre-primed canvas one can buy, of what I have seen, is from Hiromasa Funaoka, in Japan. I believe Gamblin is currently selling it in the U.S. Gamblin is at www.gamblincolors.com. I suggest inquiring there if you are interested; however, the Fredrix product is very good, and I have no complaints regarding it. I've used it myself in the past. The difference between the two is that Fredrix uses a hide glue sizing, and Funaoka uses polyvinyl acetate, which does not expand and contract with changes in humidity the way hide glue (rabbitskin glue) does. Conservation scientists have determined that this expansion and contraction due to hide glue sizing is a major factor in the cracking of old oil paintings on stretched canvas, and thus they recommend PVA sizing as preferable.

Multiple paint layers are fine as long as your earlier layers do not contain a higher percentage of oil than the later layers (fat over lean), as oil undergoes shrinkage as it ages. More oil means more shrinkage, so when the lower layers shrink more than the upper layers, problems result. Ideally, we should know what paints are leaner and which are fatter, and which are somewhere in between, without anything added to them, and make our choices of what to use in what order based on that knowledge. This is what I do, but it is too complex an issue for me to explain fully in a short message. Adding a small amount of linseed oil to the paint of each successive layer will be fine, and will simplify things quite a bit. Use an eyedropper to add the oil to the piles of paint on your palette, and mix it in well with a palette knife, rather than just dipping a brush in a container of oil and stirring it into the paint with the brush, otherwise there will be too much oil in some strokes, not enough in others, and your paint layers will have weak spots.

Regarding varnish, there are several synthetic resins now on the market that are superior to damar. The best of them is Gamblin's Gamvar. It was developed by conservation scientist Rene De La Rie, formerly of the Metropolitan Museum, now with the National Gallery of Art, in Washington, D.C. Gamblin works with these conservators and scientists in the development of his products with an eye to archival quality. Note that I do not work for Gamblin, nor receive anything for recommending their products. I only recommend what I know to be the best, and I go to a great deal of trouble to determine what is, indeed, the best. If I don't know, I will say so. Gamvar is unlikely to ever yellow, and if it does, it can be easily removed with a mild solvent that will not take off any paint that has had more than two years to cure.

The chalking of darker colors you describe is common to certain pigments, burnt umber being the worst of them in that respect. Raw umber does it too, but not as badly as burnt umber. Caput mortuum violet also does it. Learn to get along without those pigments, and you will have less trouble with the chalky appearance when the paint dries.

Good luck with it.

Virgil Elliott

[Cynthia Daniel]

Virgil,

You make reference to ATSM. Is that The American Society for Testing and Materials? Perhaps all the artists already know, but just wanted to clarify.

[Mary Reilly]

Tarique,

The Rix and Kent are both oil-primed linen.

[Virgil Elliott]

Cynthia,

Yes, ASTM is the American Society for Testing & Materials. I'm on the subcommittee for artists' materials. I will be writing a lightfastness standard for artists' pastels, with lots of help. We are currently conducting some accelerated-aging tests on them, at my urging, but I shouldn't report results until the tests have run their course.

Virgil Elliott

[Tarique Beg]

Virgil

Thanks a ton for all this priceless information! I really appreciate the time you must have put in. Hey! when you've done that book, you already have your first customer lined up. I noticed on your site you emphasized permanence. I'm sure that must be of prime concern to clients, as they would surely like to be remembered for as long as possible.

Thanks again

Tarique

[Cynthia Daniel]

Virgil,

When your book is published, you must also let us know by announcing it in the Book section here on the forum!

[Abdi R Malik]

Hello Mr. Elliott,

All my paintings formed on acrylic gesso underpainted canvas. I use liquin + turpentine for medium.

-What is your advise in order to avoid such deformation?

I prefer stretched canvas because it has bounce effect and soft touch.

-After the painting is done can I re-stretch on to the panel?

-Do you have suggestion to mount 60" x 88" canvas on panel?

Thank you
Abdi

[Cynthia Daniel]

Abdi,

I'm not sure, but there might be posts on the forum about these subjects by others. However if you specifically want Virgil's advice, I can understand, as he's very knowledgable.

In the meantime, the way to find other posts is to use the "search messages" function at the top of this page. Enter one or more keywords.

[Virgil Elliott]

Abdi,

It is important to understand that an oil paint film loses its flexibility as it gets older, and ultimately becomes brittle. So if the support on which it is applied is not stable, the paint layer will crack when the support changes its shape due to the pull of gravity, handling, temperature changes, or when there is movement in the air for any reason. This is what happens to old oil paintings on stretched canvas. When the paint cracks, the integrity of the surface is interrupted, and the lower layers are then exposed to the atmosphere, dirt, and whatever might be applied to the surface in cleaning the picture. This can weaken the bond between the paint and the ground if they are chemically dissimilar, as acrylic grounds and oil paints are. Oil and alkyd grounds achieve a chemical as well as physical bond with oil paint, whereas the bond between acrylic grounds and oil paints is physical only. Thus it is reasonable to assume that the bond will be better with an oil or alkyd ground, and the likelihood of paint becoming detached from the ground would be less than it would if the ground were acrylic. However, the biggest problem is the lack of rigidity in the support. This can be taken care of by gluing the canvas to a panel, as museums

[Abdi R Malik]

Thank you Mr. Elliott,

For your comprehensive information. I have seen enough 40 even 30 years old painting got cracked or pulled off its pigment in some part and the canvas looked as if it never been applied any pigment at all, clean no traces. The phenomena was confusing me. My late Grandfather had appreciation in art painting so he collected local paintings since 1950. As I mentioned several of them had that deformation. Then I fixed it by applying a new pigments.

Since glazing is very important method for me and I use Alkyd medium a lot.
-Does it mean I should stick my finished painting on to the panel?

Regards
Abdi