Role of Lead White in Stabilizing Oil Paint

[George O'Hanlon]

In a posting on another forum, Dr. Jaap Boon, University of Amsterdam and AMOLF and formerly head of the MolArt Project, offered these important insights into the role of lead white in oil paint film:

The role of lead white is multiple. It is a bulk drier that means homogenous drying over the paint film. It reacts with free acids that develop by oxidation of the oil. It links the acids groups of C9 diacids even when they are still acylglycerides thus stabilising the early film (proven by NMR work of Michiel Verhoeven in 2006). At a later stage when the biological ester bonds are gone, it further stabilises the diacids to form a network that is hard to break. And furthermore, it provides a filling material and surfaces for oil-derived compounds to dock.

No lead means that something else has to take over these roles. I don't think that that magical material has been found yet simply because we only very recently have begun to understand the molecular structure of paints. It is my belief that the period 1950-2000 will bring us many defects in the oil paints that are now maturing. It is time that we develop a molecular level understanding on how to deal with oil paint defects that develop when the network can't be stabilised with suitable metal cations.

My concern has been that until we develop another means of stabilizing oil paint film, artists painting in oil should continue to use lead white as their fundamental white if they are concerned about the permanence of their work. The issue of lead toxicity can be simply and effectively dealt with by good studio practice and a healthy respect of the potential of ingestion.

Of course, anyone wishing not to use lead white in their paintings because of an inordinate fear of ingesting lead and thereby developing chronic symptoms of lead poisoning, should avoid its use. We are presumably mature adults and are free to make informed decisions regarding our health.

[bart johnson]

George, this is very valuable information to have. Thanks for posting it.

I have a fair supply of zinc white pigment and have read the article you've posted about the problems with zinc, so I've largely discontinued my use of it. However, being the frugal type and given the stabilizing properties of lead you've reported here, I'm wondering if I still might use the zinc in a lead white/zinc white formulation. If you think this isn't a terrible idea, I wonder what kind of proportions you'd recommend.

[Darren]

Thanks George.
Good info to have.

[George O'Hanlon]

Bart,

Your question just came up in the Rational Painting forum, which I answered there. Basically, a small percentage of zinc oxide may not pose any serious threat (10% or less), however, the caveat is that since we do not know what about zinc oxide causes embrittlement, it may be more prudent to avoid its use altogether.

[bart johnson]

Thanks, George. I'll check over on RP, which I haven't looked at for a while and find your remarks there as well.

[bart johnson]

George, just checked out RP. I wanted to note here Ron Francis's statement that he'd been using lead white for over 35 years and had his blood tested with the lowest levels his doctor had ever seen in his surgical practice. Ron mentions he's a fastidious painter.

I'll add Lucian Freud, who was born in 1922 (if we can rely on Wiki) who's still painting strong as far as I'm aware--though I don't keep up with these things closely. I read an interview with him a couple decades back where he mentioned his use of OH Cremnitz White (lead) exclusively in his painting practice. From photos of his studio, Freud is anything but fastidious--lots of lead paint all over the walls, etc. I think it probably safe to say that if one keeps it out of cuts, abrasions and one's mouth that lead poses little danger.

But I shall await Orp's judgment before feeling really safe.

[George O'Hanlon]

I deal with more lead products in one month than most artists do in a lifetime. I have my blood checked each year and I can say that I have low heavy metal levels. I take normal precautions and wash hands before and after handling. I never eat or drink while working with such products. That is basically all that must be oberved.

[Orp]

Originally posted by bart johnson:
But I shall await Orp's judgment before feeling really safe.

I suppose you being sarcastically humorous here, but I am sure you recognize the difference between an inert metal which can sit in your system for decades until it needs to be removed and a toxic poison which will make you posthumous within a week, right?

[ 27. January 2009, 07:39: Message edited by: Orp ]

[sander]

Once again, this is valuable and validating information. Since I am prone to worry about everything I asked my family doctor to add a heavy metal screen to my annual blood test. As I sat there waiting to give the next vial, I asked the nurse to first check my insurance coverage for the 450$ test... not covered. So I decided not to worry.
Moreover, the chelation therapy to reduce toxins did not sound like a desirable process. I ordered the stack process white as a reward.

Further more, I had asked Robert Doak about this several years ago and he had given me the exact same answer that George offered above.

As far as adding zinc white in small amounts to lead, George is wise to say err on the side of prudence. However, I still reserve such a mixture for the brightest white on a relative scale, but really it's not needed.... especially in light of George's posts.

And looking way back in my history, I'm glad that I gave up holding my small brushes in my mouth during those late night moments of intense concentration. And when you discover yourself dropping your brush as Resnick described, it's probably time for bed. (Bart, thanks for that story). Of course, I have to add that Dali described getting sores on the side of his mouth while drooling during long sessions.

[DelBaldo]

[COLOR=#333333]Hello, it is known that the lead-based colors alter and blackens when mixed with sulfides (as the genuine vermilion and cadmium compounds, which usually are mixed with the zinc white). So, should we avoid cadmiums with white lead and paint with other colors substitute or is it just a legend , not completely true?[/COLOR]
[COLOR=#333333]An Italian famous book about oil painting and pigments by Gino Piva advice this way. Your opinion? Thanks[/COLOR]