Comment by mattgrice

Pinks and oranges are notoriously not lightfast. Unless you use cadmium, which is kind of not something you want to be handing out to people who might be licking their pencils. Ever notice why yellow cars always end up looking pale lemon-yellow? Lightfast non-toxic cheap red pigments aren't that easy.

Many rose/fuschia colors are not lightfast. Pigments that are not permanent are called 'fugitive' in the arts. Rose madder and alizarin crimson are not lightfast. So are a lot of others: cochineal, geranium lake. That's why you see 'green' cherubs when you visit the Getty museum also why Van Gogh's paintings are not the color they were when he painted them. Most reds for art are now quinacridone or cadmium.

One of Windsor and Newton's (oldschool paint supply manufacturer, its fun to browse history on their website) most expensive paints is 'rose madder geniune.' They claim it is permanent but I don't know how they did it.

Note: x 'lake' means x dye turned into a pigment.