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Old 15-11-15, 08:34 PM
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Koo Schadler Koo Schadler is offline
Tempera Painter
Join Date: Dec 2003
Location: Alstead, NH & Zirahuen, Mexico
Posts: 309

Thanks for the news about the casein gesso, DB. I just visited Sinopia's website, ordered a jar, and am eager to try it.

And now I’ll play the skeptic. If you want to skip the long, possibly tiresome essay that follows, here’s the gist of my post: if you’re new to egg tempera and want to best understand and make the most its potential, make a dozen paintings on traditional gesso (“TG” - an animal glue + chalk or gypsum ground). Next make some paintings on one or more of the TG substitutes (such as Sinopia’s casein gesso). Only then can you make an informed decision as to which ground works best for you.

That's the gist. Onto the long version.

I’ve tried several off-the-shelf grounds advertised as suitable for egg tempera (Clayboard, Art Boards, Golden's Absorbent Gesso) and I'm currently experimenting with another manufacturer's trial run at a ready-to-use gesso for tempera. Each has good qualities - fast and easy to use, brilliantly white, more absorbent than plain acrylic polymer gesso. But so far, in my experience, none works as well for tempera as TG.

Egg tempera loves an absorbent surface. An absorbent ground causes the water in the paint, which is the solvent for the paint, to be whisked away - this means that as a new layer of paint is applied, it is less likely to dissolve and lift the underlying paint layers. Most tempera painters agree that layering is at the heart of egg tempera, and it's hard to layer when each new stroke too readily lifts the paint underneath.

What makes traditional gesso (TG) unique is that it is composed of just two substances, both of which draw water: animal glue and either chalk or gypsum - nothing else. (This can make TG problematic in the long term; it can attract moisture which may affect a painting's durability - but that issue can be mitigated, all grounds have pros/cons, and durability is another topic altogether).

The recurring limitation of TG substitutes is that they contain one or more substances hydrophobic to water. Rather than attract water, these ingredients repel it. In the case of Sinopia's casein gesso, among other things it contains oil (hydrophobic) and a natural resin (all resins, as far as I know, are derived from essential oils). Sinopia's gesso also contains water-attracting substances like calcium carbonate (chalk) and seashells, so I don't mean to say their gesso lacks absorbency - no doubt it is absorbent. But as long as a gesso substitute contains ingredients that repel water, can it ever equal the absorbency of TG, which contains nothing but water-loving substances?

Whether this matters depends on the painter and his or her goals. Undoubtedly egg tempera can be applied on Sinopia (and other) gesso substitutes and will adhere in both short and long term. (Whether it adheres as well in the long-term is less certain). What egg tempera won't do, in my experience, is behave the same on top of TG substitutes. The paint's working properties change; the paint more readily slips and lifts (sometimes ever so slightly but enough, perhaps, to matter), which makes it more challenging to accumulate layers (and layering, as mentioned, is central to most tempera painting).

If a painter tries both TG and a gesso substitute and finds what they’re looking for in the substitute, then by all means, use the timesaving substitute. It’s a practical, informed choice. What interests me (and why I indulge in this possibly/probably tedious harangue) is what happens when a newcomer sees a TG substitute advertised as “ideally suited for…egg tempera” (Sinopia), or “the perfect ground…for egg tempera” (Art Boards) and tries tempera for the first time on one of those grounds. It’s not that the paint won’t go on – it will – but it won’t behave the same. A beginner won’t know this, and hence won’t attribute ill behaving paint to a less fully absorbent ground but instead might think such problems are inherent to the paint or painter - and, sigh, egg tempera’s reputation as an impossibly difficult medium is affirmed, and/or uncertain beginners are unduly discouraged.

Clayboard has a page on their website to explain why their product is well-suited to egg tempera: http://ampersandartsupply.blogspot.c...out-using.html

Some of their points are well made (clayboard probably does adhere better to a support than TG – although the numerous well preserved Renaissance paintings, all of which were made with TG, indicate that TG probably adheres well enough), and I agree with Clayboard that good tempera paintings can be made on its panels (I know some of the satisfied customers Clayboard mentions and their satisfaction is genuine). Again, I take no issue with experienced painters who have tried various grounds, including traditional gesso, and ultimately found success with clayboard. Rather, it’s the newcomers to the medium I wonder (worry) about. Clayboard says:

“We have received only a couple of calls over the years about lifting, but in talking further to the concerned artists and other egg tempera painters, we have found that individual technique is most likely the cause, not the painting surface.”

The company then details a specific working method to deter lifting on a clayboard panel. That clayboard necessitates these steps seems to support my assertion that it does not have the same working properties of traditional gesso. After all, my “individual technique” works very well on traditional gesso; it is problematic only on clayboard! It seems unfortunately limiting to beginners to be told there is a rigid, proscribed method one must follow to succeed in egg tempera painting, when in fact that method is requisite only when egg tempera is applied to clayboard.

I know an ET painter with decades of experience, work in museum collections, who for many years worked on clayboard. I said, “Try traditional gesso”. He switched and for several years afterward, when asked, said he wasn’t sure he felt a difference between the two grounds. This summer, in a pinch, he did a painting on Clayboard for the first time in many years. He told me he didn’t know how he had ever worked on Clayboard, that traditional gesso is much better, there is no going back. I don’t dispute that he’d previously produced beautiful paintings on Clayboard. My point is only that, in my experience, most people feel TG has noticeably better working properties than any other ground, which is important for beginners to know.

(I could also discuss the challenge of sanding many of these substitute grounds to the ivory smooth perfection that, while not requisite, is important to many tempera painters and easily obtained with TG, but already I’ve gone on too long…)

If I seem to be beating up on Clayboard, Sinopia or other companies that produce gesso substitutes, it’s not my intent. (I've ordered Sinopia's gorgeous pigments for many years and esteem their business). Egg tempera is not a commercially viable medium for the most part: pure ET paint can't be prepackaged in a tube; a well-crafted TG panel is labor intensive and expensive to make; tempera customers are few and far between. Given the minimal financial rewards it’s a wonder that any manufacturer dips their oar into the waters of egg tempera.

So, on the one hand, I appreciate companies such as Sinopia and Clayboard that produce easy to use tempera products such as off-the-shelf gesso. They save time, suit some artists, and there is a place for them. On the other hand, I’m disappointed that these products are described as equal to traditional materials and methods; they’re not. Yet it would be impractical, of course, for a company to say “the absorbency of traditional gesso is requisite for most working methods in egg tempera and is not matched by our product; however there will be some artists and methods for which our product is well suited”. I realize this is unrealistic. Full disclosure might doom the product, but lack of full disclosure is misleading. It’s a conundrum, and I'm sympathetic. As a small contribution toward resolving it, I’m willing to appear as a troublesome pest by continually reiterating what I believe is the meaningful difference between TG and the gesso substitutes I've tried so far.

I’m not adverse to changes in the egg tempera tradition (after all, I paint with makeup sponges and am trying aluminum panels, among other things) and hope I don’t come across as a closed-minded, stuck-in-the-Renaissance-mud windbag. My intention is to encourage what are, I believe (from my own experience, the overwhelming majority of full-time tempera painters I know, and hundreds of students) the materials and practices most likely to bring about success in egg tempera, because I think egg tempera deserves to succeed.

It also seems necessary to say in the ongoing conversation about easy-to-use materials for egg tempera that, compared with other mediums, tempera generally requires a bit more hands-on labor. For most tempera artists that work is sometimes challenging but mostly enjoyable and fulfilling (and in part why they love the medium). There’s nothing wrong with instant art supplies (there are many good things about them) and I’m not opposed to speeding up the painting process (as long as an expediency doesn’t compromise the work). But there’s also a place for a type of painting that takes knowledge, time, patience, effort.

This ramble is not meant to negate DB’s posting about casein gesso. Thank you, DB, for buying, trying and mentioning it. I'm eager to try it myself (and if it works beautifully I'll eat my humble pie and tell you). I mean only to say that "if you’re new to egg tempera and want to best understand and make the most its potential…" (refer to beginning of this post for rest of statement…)

Anyone who has gotten this far, thanks for listening. Comments, corrections and critiques are welcome.


Last edited by Koo Schadler; 10-02-16 at 05:05 PM.
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