MITRA Forum Question Details

​Keep in mind that I am a studio artist, not a conservation expert, and I didn't participate in creating the MITRA resources documents. I can tell you from experiece that it's a lot easier to control surface sheen by applying matte varnish over gloss than the other way around. It's probably unlikely that W&N will disclose what specific resins are used in their varnish, so you should probably plan to test a few products, with focus on ones that use the same carrier solvent. I don't see any problem with adding a cold wax matting agent to retouch varnish, but layering on top of such a mixture could be problematic, if you plan on top-coating with a final varnish layer. Also, remember that while picture varnish can be considered by the artist as an integral part of the final pictorial effect, there's a chance that your original varnish might be removed, and your desired matte finish lost with it. Many artists just use matte varnish to solve tricky lighting issues and would not necessarily care if a gloss top coat were later used, but it sounds like you really want these pictures to be viewed with a matte finish. It seems to me that it would be a good idea to document this preference in some way, for the benefit of collectors.

This is a big subject, but what you mention is true. However, this procedure works best when the high molecular weight coating (or even a similarly MW, gloss coating) is not soluble in the same solvents as the upper-most varnish. For instance, apply a xylene soluble b-72 varnish and then apply a regal-rez or other less polar varnish on top of that layer. The 2nd coating can be a matte or satin varnish. The essence here is that the topmost varnish does not overly bite into the preliminary, or saturating varnish. If you have the capability of spray application, the necessity of differing solubilities is greatly lessened.