First, we always recommend Claybord for Egg Tempera. Here’s why:
1) It has a very absorbent ground that is made with kaolin clay. Claybord provides a very smooth and absorbent surface similar, in behavior only, to a “traditional” non-acrylic gesso ground or the chalk grounds used during the Renaissance. Over the years, we have continued to increase the absorbency of the Claybord.
2) We have never used rabbit skin glue in the Claybord formula. Our tests showed that Claybord’s clay ground, when made with a minimal amount of polymer binder instead of rabbit skin glue, holds to the substrate much more effectively. Note the added plus of Ampersand’s “Archiva Seal” barrier technology. Prior to applying the absorbent clay ground to the substrate, we seal the rigid hardboard with our panel sealers to ensure that over time, you do not experience support induced discoloration that can come from a poorly prepared wood panel.
3) We have strong relationships with many professional egg tempera artists that use Claybord successfully for their work. 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.
Examples of exquisite artwork by artists using egg tempera on Claybord: Ampersand Online Gallery (egg tempera only).
Listed below are a few good practices to follow when working with egg tempera on Claybord and most other surfaces. These practices are provided by artists who use Claybord exclusively for their work as well as from Robert Massey’s book, Formulas for Painters
The important keys to working with egg tempera on Claybord are:
a) How you apply the first layers of paint and
b) Ensuring that you allow each layer to dry before beginning any fine detail work
When using egg tempera, begin by using three to four thin washes of paint over the entire panel, allowing them to dry thoroughly in between. The first four layers should dry overnight to allow good adhesion for subsequent layers. Use a very large brush and stay away from detail work in the beginning stages. After the preparatory layers are finished, alternate to smaller brushes. Continue painting in thin layers, allowing adequate drying time in between. Gradually increase the paint thickness as the layers develop. Repeat the previous step many times, gradually narrowing the size of the brush as the painting progresses. The paint consistency in the final stages should be relatively thick so that the vibrancy and character of egg tempera is thoroughly enhanced. After adequate drying time is complete, buff the finished painting with a soft cloth and frame as desired.
Much of the information about Claybord located on the Society of Tempera Painter’s Website is incorrect. We are working with them to resolve the problem.
With regard to using hardboard as a substrate, a thorough discussion is provided here on the Ampersand Website.
Also, with regard to rabbit skin glue, here is an article we found interesting written by Virgil Elliott.
We welcome your questions and comments. Feel free to post them here or contact us directly.