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TEStubbs
10-18-2012, 09:52 AM
As a Materials and Techniques professor I have always questioned the claims made by the Ampersand Company. I recently went to a gallery to look at an Egg tempera painted on Ampersand Clayboard to inspect it for flaked paint in many areas. I found that the clayboard does not allow for actual absorption of Egg Tempera paint into the surface like true Chalk Grounds do. Numerous chips of very thin paint were flaked off the surface of this rather large elaborate painting. I would understand the chipping-flaking if the paint was applied too thickly but this surface should have looked more like fine crumbling and disintegration of paint layer. Most of the flakes were around the bottom vulnerable part of the panel in the layer of black paint and on the foot and toes of the nude figure. I would understand abrasions but flaking of paint does not look consiistant with the kind of thinly applied material used! Has anyone else had problems with Ampersand Clayboard grounds?

Mayberry
10-18-2012, 07:09 PM
I am curious about this. I have two egg tempera paintings on Ampersand Claybord, and am starting a third. So far I find the Claybord to be very absorbant. It takes me quite a few layers of painting before the paint seems to be actually on the surface of the board rather than sinking in. That's when it starts developing the faint sheen. My completed paintings are both still less than a year old, so I wonder what may happen as they age. The only time I have had a bit of flaking (so far) was with a bit of prussian blue. It flaked within a couple days. I figured I tempered the paint incorrectly, and fixed it with better-tempered paint.

karenlee
10-18-2012, 07:56 PM
I had adhesion problems with egg tempera on Ampersand clayboard so I quit using it. I just get correctly prepared gesso boards from True Gesso now.

Mayberry
10-18-2012, 09:45 PM
Karen, what happened to the paint on your Claybord? Did it flake off? Did you have problems right away, or did it happen after months? years? Did it come off in layers, or did it come off all the way to the white of the board? Did the paint sink well into the clay surface as you painted? Did you have an underpainting below the egg tempera, such as with ink or watercolor? I'm worried now, wondering whether I should continue on Claybord.

Mayberry
10-18-2012, 09:56 PM
Another question to Karen (or anyone else having problems with Claybord), do you apply a varnish or anything else besides egg tempera as a final layer? (So far I haven't used anything on top of the egg tempera.)

Also, I once read about someone concerned about water seeping through the clay, into the board, causing the clay to eventually separate from the board. Ampersand says that won't happen because the way the board is sealed, but I wonder if there are incidents of that happening. I am a bit paranoid about getting my board too wet and tend to give it plenty of time to dry between painting sessions.

TEStubbs
10-23-2012, 12:22 AM
I have discovered what the problem was with the Ampoersand panel I was looking at to restore. As it turns out my speculation was wrong, the reason why the egg tempera was chipping off the surface was because the frisket film adhesive used for stenciling in the image non-image areas migrated into the panel making the paint not stick in those areas. As a warning to those who use Frisket film for paintings that take a long time to complete, frisket film adhesive migrates into the surface reducing the otherwise very porous surface of the panel. A closer look with my Optivisor I noticed that the areas where the stencil was cut paint was bubbling-blistering off because the blade was pressing the adhesive in to the surface as the cuts were being made, also a line was incised into the surface. Egg tempera requires a very absorptive surface any impediment to this absorption will cause the egg tempera to dislodge from the surface. Of all of the Egg temperas I have done on Ampersand Clayboard I have never had any problems with adhesion, it is every bit as absorptive as true Chalk ground panels. Also, though egg tempera does not require that much egg yoke concentration to water to bind the pigments to the panel be sure to check a sampling of it on your palette by laying out a thin layer of the paint, after it dries scrape it off the palette to see if it crumbles or comes off like pealing skin off the surface. If it crumbles there is not enough binder in ratio to the paint.

As for water soaking through the panel to the underlying ground that can happen with any porous ground even Chalk Ground which is made of Rabbit Skin Glue and chalk. If you are using that much water there's a good chance that you are compromising the egg yoke binder. Ampersand seals up the underlying surface to not only prevent this from happening it also keeps the panel from leaching through the ground to the surface.

As for Prussian blue and other pigments they require more binder than other pigments. As stated above check it out on your palette and scrape it off. The fact that it is absorbing into the panel with many layers is a testament to the absorbency of the surface and therefore a matter of how you are combining the pigment-binder-vehicle ratios. Egg tempera is not a medium that you can apply in broad washes like watercolor, nor is it an impasto medium, it has its limitations.

Mayberry
10-23-2012, 01:22 PM
Ah, masking fluid. I have heard of people using it on egg tempera and it sounded risky to me. I've never liked the stuff and will continue to avoid it.

charlestoncaine
06-05-2013, 10:59 PM
As ET is a medium requiring a rather meticulous approach it puzzels me as to how masking fluid would be of use. As one can overpaint on ET using opaque pigments where would maskinhg fluid be of use?