Here Blake has used Prussian blue, indigo blue, vermilion, a red lake (probably brazilwood), another red lake with a pinker tone, and yellow gamboge. He never used madder, the most stable of the red lakes, as it was too expensive.
All his pigments, except for vermilion, are sensitive to light, so it is fortunate this watercolour has not been exposed to too much light. Indigo blue and the red lakes fade faster than gamboge. This is because the gum Blake added to make the gamboge look glossy has protected it.