MITRA Forum Question Details

I'm not a conservator, merely well read on the s​ubject.

Sulphur (I'm not American.) is hardly a risk to lead white in most locations nowadays, and even when it was back in the smokey 19th century, it was mostly in the outdoors and open doored churches.  Some places with hot pools with rotten egg smell (that the locals become blind to.) have shown a recent effect with unvarnished or unglazed paint, but the effect is generally overstated with oil paint.  Watercolour lead white is another matter.  Without the binding oil this discolours more freely so no one, as much as I'm aware, makes it anymore.

As a completely covered ground layer it should be as close as one can get to being completely risk free.

Titanium is much more opaque than lead white, it is true, but not as strong a paint film as lead white.

Marc.​​

​Thank you so much for your comment, Marc​. 

​Indeed, his statement seemed kinda strange, hence my interest in checking out the information in this forum. My idea then would be to apply one or two thin coats of lead ground on top of Lascaux Acrylic primer. It is slightly absorbent, good for preventing excessive sinking in, but I will have to test how well oil ground adheres to it. 

Apart from that, do you have any thoughts on using either a lead oil ground or a lead alkyd ground? I am looking for the most archival option, I don't know if one of the two is more desirable. 

Thank you again for your time. ​

​I haven't tried the Lascaux acrylic primer, but if it's intended as a universal primer it SHOULD be good for what you intend.

I believe the smithsonian did some paint film tests on lead oil paints. I should state the study date and number and if I can found it easily I will quote it later.  I recall that the lead white alkyd was too hard after many years of aging, as was lead white made solely with litharge black oil.  Both prone to cracking, while the normal lead white in standard refined linseed was in what might be called a Goldilocks zone of not too hard, not too soft.  So without having personally tested the lead alkyd ground. I'd go with the lead oil ground.

Marc.​

​​Study: The Influence of Pigments and Ion Migration on the Durability of Drying Oil and Alkyd Paints.  by Marion F Mecklenburg, Charles S Tumosa and Edward P Vicenzi. 2010.    

The lead white was in cold pressed linseed, not refined linseed, and the brittle lead white alkyd 29 years old.  The lead white alkyd wasn't a ground, but a Winsor and Newton Griffin alkyd colour.  The Griffin flake white is now discontinued.  

Marc.​

​​Thank you so much again for the thorough information, Marc.

​Yes, the primer is universal, although I have been adviced by one member of Jackson's to not use that  primer before an oil based ground ​due to potential adhesion issues, I guess due to the primer's slight absorbency. So it's one or the other, apparently. ​​According to Natural Pigments, their Lead alkyd ground is designed to adhere to ACM (where I plan to paint), ​so I may have to test all options , although budget-wise that's a bit inconvenient due to their pricings. ​​

I will be checking options, and if ​

​I will be checking options, any advice on this matter would be gratefully appreciated* 

(Apologies, message got cut for some reason). 

Lead ions in the ground apparently migrate into the paint film, which enhances its stability. However, lead white (PW 1) ground with zinc oxide white (PW 4) is even more brittle than when zinc white is ground with titanium white (PW 6).

​Therefore, a ground with lead white in it may be better for long-term stability or worse, depending upon what is mixed with the lead. Some alkyds have shown high brittleness but others may not have this defect. I presume, for instance, that the paint line "Archival Oils" is made with an alkyd, although I don't believe the company has disclosed what it uses. One amateur's test found that it, unlike the titanium-zinc white blends, did not crack nor delaminate. Similarly, two other brands of white that did not contain zinc oxide did not crack, nor did they delaminate. One was Lukas' "Opaque White" that is made with PW 5 (lithopone) and possibly some wax. The other I can't recall but I think it was also a lithopone white.

A lead + titanium ground, I would imagine, would offer both the superior brightness and opacity of titanium, with lead ions to enhance the paint film's stability. I really can't advise about the addition of alkyd.

Calcium carbonate and barium sulfate have also been components (additivies) of lead grounds that appear to be stable. However, I am not a professional conservator/researcher so take my words with due caution.

My advice is to avoid zinc white and grounds using animal glue. My understanding is that animal glue (rabbit skin, sturgeon, et cetera) has inferior properties when compared with some modern synthetic alternatives.

— SRS