Is shellac a good ground?

Rod Lamkey · 03-02-2005, 08:46 PM

Is shellac a good ground for oil painting? I brushed a thin coat over traditional gesso on Masonite, and it is an ideal surface. But does it stand up over long periods of time?

Thank you,
Rod Lamkey

Allan Rahbek · 03-06-2005, 05:33 AM

Hi Rod,

Shellac has been used under oil paint for centuries to isolate the pine sap from bleeding through the paint. There has never been any problems with the oil paint not adhering to the shellac.

But the shellac is non absorbent and may be different from a gesso ground when starting the painting.

Allan

Richard Budig · 03-18-2005, 09:59 AM

Norman Rockwell said (in a book of his that I was reading) that he often used shelac to cover, protect, and isolate his drawing before he began to paint. He said that way, if he got into real trouble, he could wipe off the paint and recover his original drawing. I've never tried it, but it sounds like it would work. I still have the book somewhere (I think) if you want the exact source.

Rod Lamkey · 03-18-2005, 10:01 PM

Thank you for the input about shellac. I gessoed and sanded smooth a few Masonite panels, then put one coat of shellac over that, and it gave me an ideal surface for precise painting. It is great for grisaille, for paint wipes off easily creating lighter tones than was possible without the shellac.
Thanks again.
Rod

Juan Martinez · 03-27-2005, 11:14 AM

Hi Rod,

I haven't posted for a while, but used to quite a bit. Hope you don't mind if I add my two cents worth.

Actually, shellac shouldn't be considered as a painting "ground". It may have been used as such from time to time, but people also paint on glass, wood, and metal, too, and none of those are considered "grounds". At any rate, shellac was traditionally used to treat chalk-based gesso, a true ground, to cut its absorbency which can vary from batch to batch and is usually a little too much. However, there are two problems with shellac, one of which you have dealt with already.

First, shellac is prone to embrittlement and darkening. Since you are using a panel, which won't deflect as much as stretched canvas will over time, the brittleness shouldn't be a problem. And, since you're using it underneath the painting, rather than on top as, say, a varnish, its darkening shouldn't be a problem, either.

The second thing, though, is that shellac can form an impervious layer which will not allow a proper mechanical bonding of the oil paint with the gesso, which is what oil paint and gesso are supposed to do. Shellac should be thinned with methyl alcohol before being applied to gesso so that it soaks into it, rather than forming a layer on top. This should cut the absorbency of the gesso somewhat, but still allow the oil to penetrate to a degree. It's a rather vague target, at best.

For sketches and the like, painting on shellac might be alright but you're otherwise compromising the permanence of your work.

As an aside, this is very much the problem found on many of Norman Rockwell's paintings; they are darkening and cracking ...all sorts of things are happening to them. Some of this could be due to the shellac, some of it to the kinds of oils and driers he may have used, and who knows what else. Not all of his paintings are deteriorating, mind you, but many are. I suppose he didn't do the same thing to every painting and, he probably experimented a lot, too. As a successful commercial illustrator, he was concerned with speed and not always with permanence. So, whatever got him to his conclusion the fastest and most efficiently, that would be what he did. As much as I love Norman Rockwell's paintings and his abilities, I wouldn't follow his technical practices. (With respect, Richard).

Hope it helps.

Juan

Juan Martinez · 03-27-2005, 11:18 AM

Hi Rod,

I haven't posted for a while, but used to a little bit. Hope you don't mind if I add my two cents worth, here.

Actually, shellac shouldn't be considered as a painting "ground". It may have been used as such from time to time, but people also paint on glass, wood, and metal, too, and none of those are considered "grounds". At any rate, shellac was traditionally used to treat chalk-based gesso, a true ground, to cut its absorbency which can vary from batch to batch and is usually a little too much. However, there are two problems with shellac, one of which you have dealt with already.

First, shellac is prone to embrittlement and darkening. Since you are using a panel, which won't deflect as much as stretched canvas will over time, the brittleness shouldn't be a problem. And, since you're using it underneath the painting, rather than on top of it as if it were a varnish, its darkening shouldn't be a problem, either.

The second thing, though, is that shellac can form an impervious layer which will not allow a proper mechanical bonding of the oil paint with the gesso, which is what oil paint and gesso are supposed to do. Shellac should be thinned with methyl alcohol before being applied to gesso so that it soaks into it, rather than forming a layer on top. This should cut the absorbency of the gesso somewhat, but still allow the oil to penetrate to a degree. It's a rather vague target, at best.

For sketches and the like, painting on shellac might be alright but you're otherwise compromising the permanence of your work.

As an aside, this is very much the problem found on many of Norman Rockwell's paintings; they are darkening and cracking ...all sorts of things are happening to them. Some of this could be due to the shellac, some of it to the kinds of oils and driers he may have used, and who knows what else. Not all of his paintings are deteriorating, mind you, but many are. I suppose he didn't do the same thing to every painting and, he probably experimented a lot, too. As a successful commercial illustrator, he was concerned with speed and not always with permanence. So, whatever got him to his conclusion the fastest and most efficiently, that would be what he did. As much as I love Norman Rockwell's paintings and his abilities, I wouldn't follow his technical practices. (With respect, Richard).

Hope it helps.

Juan

Rod Lamkey · 03-27-2005, 12:06 PM

Thanks, Juan, for the information about shellac. I've been telling people that their portraits will last 'for generations',. As I've only used shellac to cut down the absorbency of traditional gesso so far, the paintings I've done to date will probably last.

Meanwhile I find myself between two schools of thought: some friends insist that traditional gesso, with rabbit skin glue, is the only way to go, while everybody else says that acrylic gesso, with titanium white, is just as permanent. The traditionalists imply that acrylic gesso may not be archival.

You cleared the air to my satisfaction and I know what to do. Now I am wondering about various kinds of plywood, but I'll add a different post, for that..
Thanks again, Juan.

Rod