Oil paint whites

There was a question which might not be noticed as it was posted in the book reviews section, on the back of my thread about Virgil Elliott's reprinted and updated Traditional Oil Painting. So I thought I'd briefly address it.  Virgil is a great exponent of lead whites, and this led to the question, basically, what's wrong with Titanium White, then?   Nothing, is the answer.  Titanium White has been around for a long time, and its use presents no problems.  It does not make as strong a paint film as lead whites - but that's really not much of an issue, especially on rigid surfaces: stretched canvas is good to paint on, but it never was an ideal support for oils - and some find it chalky and cold, overpowering delicate tints: but that's not a technical  problem, and anyway, it's a matter of opinion. The problem pigment in oil - not in other media - is Zinc White; slow-drying, brittle when dry, and linked to cracking and delamination.  Zinc is often added to other colours, including Titanium White, and Naples Yellow Hue.  But we've been here before, and I only wanted to answer a question, not deliver a lecture!

Trevor - the evidence is conclusive that Zinc White causes embrittlement of the paint film; the snag is, no one really knows as yet whether this is a problem with paints in which it's mixed.  Its action isn't uniform, either: there are paintings of around 200 years old, in which we know the artist used Zinc White: and at least one of them is still in almost pristine condition.  The problem it poses would be extremely exacerbated if a canvas were removed from its stretcher and rolled, as used to happen when shipping them: but then - that's always a bad idea, Zinc or no. The alarm about Zinc was first raised by conservators, I think, who noticed extensive damage to oil paintings produced in relatively modern times - eg, some Impressionist works - while old masters' paintings didn't exhibit the same characteristics (though many of them cracked, the paint adhered).  Zinc was identified, after a great deal of research, as the villain.  If you don't sell, and if you're not bothered by your paintings developing problems in 30 to 50 years, then I wouldn't worry at all.   If you're worried just a little bit, painting on a rigid surface, not stretched canvas, will help.  What happens though if you get good enough as a painter that people urge you to sell, and you yield to their entreaties?  You'd probably have to reconsider your painting habits. Paintings in oil deteriorate for all sorts of reasons - bad technique, excessive use of mediums, using unsatisfactory mediums to start with, and use of problematic pigments; avoiding Zinc makes sense because, with all the things that can go wrong, it's advisable to remove those optional extras which can combine with others to make your painting look like a battered eggshell (fine if that's what one intended; not so great if one didn't).   But I say again - none of this applies to Titanium White (PW 6), unless perhaps it's mixed with Zinc White (PW 4); and even in the latter case, we can't be sure.  I would keep an eye on the research, particularly that undertaken by MITRA at the University of Delaware - it develops all the time as new tests are performed.