Alizarin Crimson Substitute

After recent discussions with a talented artist regarding the lightfastness of alizarin crimson, I've started poking around for a substitute. Irgazine Ruby DPP (Diketo-pyrrolo-pyrol) seemed a likely candidate. Kremer rates it top of the scales for lightfastness.

The dry pigments clearly show differences but I've learned not to put much stock in dry appearances. All images are with Irgazine Ruby (PR264) on the left; Alizarin Crimson (PR83) on the right.

PR264                  PR83
Dry Pigments

Although blurry, I think when the autofocus got confused with the glass palette, the colors seem closer.

Pigments mixed with egg medium

Here the colors seem to veer off with the PR83 leaning a bit towards blue. Still, seems pretty close.

Test strip.
Mixed pigments diluted with water
on the top half and titanium white below.

I'm reading about PV19, a quinacridone, as another possible substitute. There are two colors, leaning either towards red or blue, with this same pigment code. More on all this later. I just felt the need to try out a little test here with in stock pigments.