If it is 1.3% aqueous it is saturated (as much picric as distilled water will disolve) and will dye your feathers the best. I think that 50grm is all you are allowed but I will update later with more details.

To dye the feathers, just soak them in the solution for up to 24 hours and rinse until the water runs clear. 100ml will be enough for most feathers.


Brennan