Did you know there are actually four shades of indigo? There's indigo as it appears in the spectrum (i.e. the rainbow), indigo as in the plant used as a dye, the web color indigo, and pigment indigo (the kind used in paints). Check it out!

http://en.wikipedia.org/wiki/Indigo#Dis ... _of_indigo

Pigment Indigo is my favorite and the one I typically think of when I picture the color indigo.

Neat find Pigment is not fun to mess with...all powdery and stain-y... but is fun to put on a mill or in a banbury and watch the colors mix!