I don’t own any tubes of purple gouache. I recently have been using a lot of purple. Having to mix it each time doesn’t bother me, but I never seemed to be able to get the color right. I tried different combinations trying to find a good one, to no avail and much waste of paint. I’m certain I mixed the same shade of purple mud half a dozen times. So I gave up and made a color chart. For the limited audience who is curious about mixing purple gouache, here you go. You’re welcome.
A few notes: all the colors were Holbein, except Ultramarine – that was M Graham. All the paints were single pigment. These are all the reds and all the blues I have. This chart should be just as good for watercolors as for gouache. I have concluded that having both Alizarin Crimson and Pure Red on hand just makes things more confusing. I can tell them apart on the palette only because old Holbein AC crumbles into little bits when it gets dry.
Holy moly, I’ve had some of my gouache tubes for 3 years. No wonder they’re getting crunchy.