MITRA Forum Question Details

I've tried watercolor on "traditional gesso" (animal glue + chalk/gypsum ground) only a few times - so, I'm no expert in that respect - but I do have many years' experience with egg tempera and metalpoint on traditional gesso (TG).  TG is, overall, a very absorbent surface.  By varying the ratio of glue to solid particles, you can somewhat vary TG's absorbency: the higher the percentage of glue, the harder and slightly less absorbent the ground; the lower the percentage of glue (and correspondingly, the more solid particles) the more absorbent and somewhat less hard the surface is. 

The degree of absorbency affects how readily the surface takes up water.  For watercolor, if you have too much absorbency you won't have much time to manipulate the paint.  An artist can play with the degree of absorbency, to some degree, to figure out what works best both for the artist's medium and working methods.

Traditional gesso is so absorbent that for some mediums - oil, for example - it takes up too much binder and the paint can be under bound; this is why it's often recommended that oil painters who work on traditional gesso first cut the absorbency with a size of some sort (animal glue, shellac).  Does the same holds true for watercolor, could the paint be under bound on a very absorbent TG surface?  I don't know - hopefully an experienced voice will comment.

I believe it's critical to coat any surface that has wood grain (solid wood, plywood) with cloth (cotton or linen) before applying gesso - otherwise the grain pattern can telegraph through the gesso and create hairline cracks.  I've seen this occur in paintings that are decades old; I've also seen it happen very quickly, on newly applied gesso, when a student used very water intensive methods.  So I always apply cloth atop wood grain.  Fiberboards, which don't have a grain, don't require cloth.

Perhaps you have a more sensitive touch than I, but after decades of working on traditional gesso I have never felt the tactile softness of the underlying cloth - my gessoed surfaces, both on MDF (no cloth) and plywood (linen), feel the same: absorbent, relatively hard, and amendable to crisply painted lines in egg tempera.  How many coats of gesso did you apply?  And what was the ratio of glue to solids (chalk)?  I apply at least 9 layers or more, which fully covers the cloth, so there's no hint of its presence.  Perhaps that's the difference.

Hope that helps, Koo Schadler

One more thing to mention....I don't believe you need to use a traditional, artist's portrait linen, which can be quite thick.  Granted, a thick cloth would provide an optimally protective layer between wood grain and gesso - however I generally just use a fine linen from the fabric store: not too thick, tight weave, no knots - it works well to cover the grain yet is quickly filled in and fully covered by gesso. ​

​Koo

​Yes, a collage of fabric may have caused the softness.  If you're willing and able, please share what you learn about watercolor on traditional gesso - I'd be interested. ​