The St Petersburg Master Class Oils range does have PY32 Strontium Yellow for those that are interested.

The pigment is so nice and delicate. I have some of it in raw form. Sadly, it isn’t very permanent.

Where did you hear that PY 32 not very permanent? Several manufacturers list it as completely lightfast ([B]with possible minimal shifting toward green[/B]).

Which is very definition of being impermanent.

From ArtIsCreation:

may turn greenish due to the partial conversion to chromium oxide

source

Guess you guys did not read the pigment manufacturers information on the pigment then… the warning about possibility of it turning green is an effect caused by certain chemical exposure. It is still considered lightfast because very specific sets of variables are required to cause the color to change.

Want to know another yellow considered highly lightfast, but in fact will darken in some media or fade when exposed to excessive light? PY 35, happens when the pigment becomes exposed by remove of the binder through the use of solvents commonly used in oil painting. Nothing is permanent or lightfast if the conditions are not right for it, I just suggest we stop trying to make everything out to be less than what it is.

From a chemical analysis point of view, PY 32 seems to be a solid color, though it’s most common use seems to be in industrial coatings which often get exposed to various highly unfavorable conditions (radiation, corrosive and caustic chemicals, and many others).

Guess you guys did not read the pigment manufacturers information on the pigment then… the warning about possibility of it turning green is an effect caused by certain chemical exposure. It is still considered lightfast because very specific sets of variables are required to cause the color to change.

There is a Russian State Standard GOST 11826-77 for artist’s oil paints, a document similar to ISO and ASTM standards. It states that Strontium Yellow oil paint is marginally lightfast and changes color significantly after 5 months of exposure to direct sunlight, from May to September. Manufacturers could make it better than this standard demands, but no means are able to make the paint completely lightfast.

Roman, it appears that your document is over 40 years old… pigment technologies have improved quite a bit since then and the pigment that was tested for that document may well have been of a poor quality in itself. These issues arise in ASTM and ISO standards as well, except that the standards are revised a bit more often usually.

Further exploration has many manufacturers now days claiming it at a very high lightfastness rating (usually 8 on the BWS).

Roman, it appears that your document is over 40 years old…

The Standard has three revisions and the last one is not so old, but I doubt that pigment’s properties changed significantly. Other Russian paint manufacturers also mark it as marginally lightfast, with one *. Gamma, Podol’sk. Maybe there is a method to improve its lightfastness, like adding Tinuvin light stabiliser, I don’t know if they use it.

Correct me if I’m wrong but is this row referring to Viridian Green?

No, it is PG 8 Nitroso Green. Here you can compare some commercial names with pigment numbers, sometimes it helps, but not much. For example, Volkonskoite a natural mineral which mostly consists of PG 17 Chrome Oxide Green, yet they write it as PG 23 Green Earth. It is indeed Green Earth, but not the same as Glauconite or other minerals.