This was an important synthetic orange for painters, but perhaps it may be less interesting for oil painters after some recent lightfastness research about mixing whites. We are especially grateful to Golden for bringing these issues to light in their recent testing on oil paints. It turns out that PO73 is surprisingly reactive to certain white pigments in oil painting. Were it not for the lightfastness issues, it could have been a possible alternative to the redder forms of Cadmium Orange, but it is less opaque and is also unfortunately a bit more sensitive than was once thought.

Aside from the reactivity, its masstone is a stunner. Pyrrole Orange creates gorgeous light orangy-pink tints. The tints are higher chroma than cadmium red or orange, so PO73 was nice if high saturation is desired— however watch those mixing whites and blending oils. Pyrrole Orange makes what may be the very best red-orange tints with a hint of a pink undertone.

In masstone it's blazingly high in chroma.

Most give this pigment high ratings for excellent lightfastness, however there were some strange curveballs found in oil paints depending on the precise mixing white used. In the recent testing by Golden, PO73 seemed sensitive to binding oils as well, specifically Safflower Oil (more details below). This finding may be significant as several companies offer this pigment in a safflower oil blend. For more, consult Golden's recent research on lightfastness in oil paints.