A new paper released by scientists at the Smithsonian's Museum Conservation Institute exposes long-term problems with zinc white in oil paint.
This post is merely an introduction to this problem and I urge you to read the entire study on the link above.
Zinc white oil color has a BIG drawback; it makes a rather brittle paint film.
Zinc whites' brittleness can cause cracks in paintings after only a few years, if it is used by itself and in excess.
Should artists toss out their tubes of white oil color containing zinc white?
The answer is YES . . . if you want your work to be archival.
The above detail of a painting by Henry Cliffe, painted in 1959, shows severe cracking and peeling (from rolling the painting) in paint containing a combination of both lead white and zinc white.
The majority of white oil paint available today includes zinc white.
Even "Titanium White" or "Flake White" may likely contain Zinc White (not always listed on the label). Ouch.
Of course, not every painting containing zinc white will crack and its paint fall off the support.
Ophelia (1852-97) by John Everett Millais has areas of zinc white priming. Remarkably, the painting is in generally good condition and does not show problems.
So why is zinc white is so commonly found in white oil paint today?
Zinc white is transparent, nontoxic, doesn't darken and offers a brilliant white allowing artists to obtain highly saturated colors.
In the past I have used Zinc White in small amounts because of its transparency and ability to "cool" an area.
Right now I am using "Titanium White" and hope it doesn't have much (unlisted) zinc in the ingredients. I use a very small amount of Titanium white in Liquin (or any medium) as a thin scumble to replace the zinc white paint I used to use.
So, if any reader knows of any high quality artist's white oil paint that does not contain lead and/or zinc, please let me know.