Handmade indigo watercolor made of plant-based indigo extract (organic Indigofera Tinctoria).
If you paint skyscapes or looking for a way to darken greens, browns, or blues without turning them into mud, Indigo is the way to go (especially if you avoid using black!).
Indigo can be used as calligraphy ink, too - just dissolve it in water.
Available in half pans and full pans.