Greg Scheckler wrote:
I just found out also that sometimes on paperboard it was okay to use glue-size on the front and back (rabbit skin glue) and then seal the painting surface with turpentine-diluted damar varnish, which is at least a lean layer that you could oil paint on. It seemed like the glue size would be too brittle for just on paper, not board.
Virgil, can you verify if historically that sounds reasonable?
(Your acrylic sealing and then gessoing is a lot easier!!!)
I just found out also that sometimes on paperboard it was okay to use glue-size on the front and back (rabbit skin glue) and then seal the painting surface with turpentine-diluted damar varnish, which is at least a lean layer that you could oil paint on. It seemed like the glue size would be too brittle for just on paper, not board.
Virgil, can you verify if historically that sounds reasonable?
(Your acrylic sealing and then gessoing is a lot easier!!!)
Greg,
From a historic perspective, depending on how far back in history you're referring to, damar would probably not have been the varnish used, but more likely copal in the 19th century, and possibly further back than that, the other possibilities being shellac, mastic (less likely) or sandarac. But the paperboard you mention indicates 19th century and early 20th, so I'd say most likely copal, which would be preferable to damar for this purpose.
Hide glue might well be what was used for sizing, but it is not the best thing to use today, because now we know about its tendency to subject the support, and thus the paint layer, to extreme changes in tension as it shrinks or swells with changes in humidity. On rigid wood panels, this is not such a problem as it is on flexible supports such as canvas, and, presumably, the paperboard you mention.
Keep in mind that this was never intended to be permanent work anyway, but just studies and sketches done in the field, to be used as reference material in the execution of larger paintings done in the studio using more archival materials. Once the big canvas was painted, the studies' usefulness would have been fulfilled, and their permanence would not be a concern.
As I said before, there are better, more archival, materials available today than were available 100-150 years ago. Unless we are making fake antiques, it would be wise to consider using the best materials we can find, if we care what our creations will look like to viewers of the future.
Virgil Elliott
