I have been hearing a lot about the toxicity of lead white paint…..but some of my colleagues swear by it. I am sort of torn at the moment…
If you must absolutely use a lead-based pigment, you may want to consider lead sulphate instead of lead carbonate. It is apparently more stable. There are several resources on lead white and it’s darkening due to hydrogen sulphide in the air. Otherwise, lead is indeed pretty detrimental and eventually lethal by repeated contact, inhalation and ingestion. Laurent Cruveillier MA conservation Student, UAL – Camberwell College
If you must absolutely use a lead-based pigment, you may want to consider lead sulphate instead of lead carbonate. It is apparently more stable. There are several resources on lead white and it’s darkening due to hydrogen sulphide in the air. Otherwise, lead is indeed pretty detrimental and eventually lethal by repeated contact, inhalation and ingestion. Laurent Cruveillier MA conservation Student, UAL – Camberwell College
Lead sulfate was introduced as a non-toxic substitute for lead white (although not necessarily used often by artists). Lead sulfate was later found to be toxic, but not to the same degree as lead white (basic lead carbonate) due to it being less reactive to acids and hence less soluble in water. While it is true that lead sulfate is not reactive to hydrogen sulfide air pollution, the amount of hydrogen sulfide air pollution in industrial countries is very small so this concern is not as present today as it was in the 19th century. Basic lead carbonate forms soaps in vegetable drying oils that are beneficial to the paint film, and hence important to the longevity of the painting.
Great question….this is one of the first topics addressed in our “Myths, FAQs, and Common Misconceptions” document which can be located on the Resources Page. If you are interested in learning more about Health and Safety in general I also recommend downloading our H&S document there as well…
Thanks for your comment Laurent….certainly lead carbonate is susceptible to darkening in the presence of sulphur. However, this reaction tends to occur mostly in dry media (e.g. pastels) and leanly bound paint systems such as in watercolor and gouache. Lead carbonate is actually no longer suggested as a suitable white pigment in any of these media due to it’s propensity to react with the environment as the pigments are far more exposed than in an oil film (that, and it’s toxicity). However, lead sulphate is just as toxic….the one possible medium where I can see this pigment being superior than lead white as a pigment is in egg tempera. But in oil films it is considered inferior in all aspects: drying, covering power, and flexibility of the resultant paint film. George O’Hanlon has a good synopsis of it’s qualities which I include here: The hiding power of lead sulfate pigment is less than lead white on account of its more crystalline nature, and its drying quality is also less. Lead sulfate is either a neutral pigment of crystalline structure with poor hiding power or a basic pigment with better opacity but less than basic lead carbonate. Compared to basic lead carbonate it does not mix as well with oil. According to Laurie, lead sulfate prepared by precipitating the lead salt with sulfuric acid had poor covering power but that produced by sublimation gave the best pigment. It was a pure white, slightly ‘blue in color and covering as well as white lead.’ Lead sulfate was less used alone than in mixtures with and shading other pigments. http://www.naturalpigments.com/lead-sulfate.html
