Virgil Elliott's Traditional Oil Painting

Titanium White is not problematic - it makes a weaker film than lead whites, but nearly all of us use it.  Zinc White - well.... that's another issue entirely.  There is clear research linking it to delamination - ie falling off the canvas, in short - and cracking.  But then, we've long known that it's not satisfactory as a base coat, because it takes a very long time to dry thoroughly.  Its major problem is that it's mixed into other colours by the makers, particularly into Naples Yellow Hue - whether this turns out to be an issue in the long run, no one really knows for sure.  But I avoid it entirely, so far as I can.  It's particularly vulnerable to change and deterioration when used on stretched canvas - because canvas moves, and Zinc White is brittle.  There's a well-known painting (by Rosetti, I can't remember?) from the 19th century, in which it's known Zinc White was used: and it has shown no signs of deterioration; so the process isn't inevitable, although we don't know how the artist used it, or with what medium - so far as I know, anyway.  The science of oil painting is complicated, and knowledge advances - slowly - over many years: trouble is, none of us will be alive to find out exactly what happens to our paintings; we just have to make the best choices we can and exercise personal judgement.  Which is what Ken Howard will have done, but if I were him (my paintings don't sell for thousands, unfortunately!)  I'd think of changing my practice. Worth just adding that Zinc White is only a problem in oil paint - not a problem in acrylic, and of course Chinese White in watercolour is basically Zinc, and has been in use for a very long time (I hate the stuff, but that's another issue entirely!).