Hello Mitra,
I would like to first say thank you everyone from Mitra for their continual help.
I recently heard of teachers at an academy, that I will not name, telling their students that they could place a final varnish of a polymerized oil like a stand oil. They are told that this is actually what many of the old masters did and that other varnishes are not necessary. Is a polymerized oil, like a stand oil, suitable for this? During your experiences have you ran across any masters that did this?
Best Regards,
Hector
So recipes for oil-containing varnishes go back quite far (Theophilus writes about them in the 11th c but they were likely in use even earlier) and it is possible that oil alone was used on occasion as a coating for painted surfaces. Eventually the Old Masters sowly transitioned to spirit varnishes around the 15th c however it is clear that oil-containing varnishes continued to be used here and there. But as we know not everything the Old Masters practiced or used stood the test of time. Oil-containing varnishes are a perfect example of this….they can turn horribly brown and darken, obscuring the original palette beneath. Perhaps even worse they cross-link, meaning they become impossible to safely remove from oil- and/or resin-containing paint layers. Finally, an unpigmented stand oil film will remain tacky for a very long time, inevitably attracting dust and grime. I hope this somewhat answers your question.
I understand the appeal of historical theories about painting methods and materials, but the need for accountability to collectors compels me to use modern, reversible varnishes that facilitate easy maintenance and cleaning of finished works.
Charles Locke Eastlake is often the source for notions about use of oil varnishes throughout history. Eastlake’s theories about the use of oil varnishes by the Old Masters were influential, and are still referenced today despite even Eastlake himself remarking often at the apparent defects in paintings where oil varnishes were used. Eastlake wrote about the comparative tendencies of different fresh, semi-fossil and fossil varnishes to yellow and darken, and theorized that earlier painters employed strategies to compensate for darkening, or even use it deliberately. It’s important to remember, however, that Eastlake wrote and worked at a time when a dark, yellow cast in paintings was associated with antique age and was often considered aesthetically pleasing. http://www.mediafire.com/file/3mwymy4r2oo/methodsandmaterials_Eastlake.pdf