This is an important synthetic orange for painters, but it holds a few surprises for oil painters after some recent lightfastness research about mixing whites. It's a stunner in terms of chroma and makes lovely pink tints. However, due to its lightfastness quirks it may need to be used carefully if used in oil painting.

As to the quirks of Pyrrole Orange, this was a shock as it is typically listed as ASTM I (excellent) in oil. We are especially grateful to Golden for bringing these issues to light in their recent testing on oil paints which takes into account several previously unaccounted-for variables. It turns out that PO73 is surprisingly reactive to certain white pigments (and/or binders) 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 Pyrrole Orange is unfortunately a bit more sensitive than was once thought.

The tints are higher chroma than cadmium red or orange, so PO73 was nice if high saturation is desired— however just another reminder to watch those mixing whites and blending oils. Pyrrole Orange makes some of the very best red-orange tints with a hint of a pink undertone.

In masstone Pyrrole Orange is blazingly high in chroma. In terms of its relationship to Cadmium Orange, Pyrrole orange is less opaque than Cadmium Orange.

To delve into the lightfastness in oils a bit more, 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. 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.