MITRA Forum Question Details

​Hi all,

I have taken an internet break since the evening of the election. I will respond to this tomorrow.

Sorry for the delay.

I would suggest against using such an additive in oil paint for many of the same reasons that I do not recommend adding dammar or mastic to oil paint. No, MSA is not going to yellow nor become brittle overtime but, honestly, those are my lesser worries.

MSAs will impart their solubility to oil paint in proportion to the amount added. One of the good things about MSA varnishes and other approved synthetics is that they remain soluble in solvents of a similar polarity/aromaticity over time. This is great since when the coating needs to be removed, it can be done using solvents that are less likely to damage the oil film. When these materials (natural and synthetic resins) are added to oil paint they GREATLY increase the chance that the painting will be irretrievably damaged if they ever need to be cleaned. Please see #5 on our Myths, FAQs, and Common Misconceptions​​ downloadable pdf found in our resources section.

If you feel the need to experiment with MSA varnish (or any soluble resin) as a paint additive, please make sure that you record this info somewhere (safely, not drawn on the back of a canvas, etc.) on the reverse of the painting (preferably on the stretcher bars if it is on fabric).

Finally, I would advise against varnishing such works and recording this fact (as above) so that no one inadvertently tries to clean it with solvents. This would not occur if the painting is being treated by  conservator who would do all sorts of tests, but my experience is that there are just way to many DIY “restorers” out there. Their misguided efforts are the reason for about half of the conservation treatments that we receive.

I would really suggest using one of the more fluid alkyd painting mediums for your attempts to reconstruct the richness of Parrish’s glazes. Yes, he did sometimes use dammar in his layers, but he also often used copal varnish/medium as his additive. While the later will darken and perhaps impart brittleness, they at least become less soluble over time.

Even if this were the case, and I am not sure that it is, the increased solubility would vastly outweigh any benefits that could be derived.

OK

It is interesting in that MSA could be considered a synthetic soft resin like dammar whereas an alkyd medium is a synthetic resin-oil medium analogous to copal-oil. Their handling and aging properties as quite different, though.