Re: alizarin crimson and lightfastness
If IRC there is no actual pigment "alizarin crimson" -- but a free-floating designation the manufacturer can tack onto whatever they please. An actual *pigment* is either manufactured or mined, like "ultramarine" or "lamp black" or "burnt sienna" -- by a specific process or from a particular set of hills...(I forget what the color was called, but apparently the mine gave out for my favorite acrylic paint, called something like maybe "Venetian Red." The company put a color in a jar labeled "Venetian Red" but it wasn't the same -- so I had to take up photography.) The term "alizarin crimson" is of course used for something suitably red, tho -- for whatever reason, there are other alizarins. For instance my ancient Rowney watercolor chart shows aomething called "Brown Madder (alizarin)" And I notice that the same chart has a red called "crimson alizarin." (I suppose they're hedging.) In any event, I think the term has been cast into disrepute, that is, not used any more in better paint circles. PS. My most recent (that is, 2006) Daniel Smith catalog does list an alizarin crimson watercolor which it gives a rating of "IV" (that's Roman Numeral 4) -- designated "Fugitive." I've found the quinacridones similar in tone and generally lightfastness rated "excellent." J.
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