But it's tough to move beyond these three distinctive, earthy tones. We have some fine media in red and blue, and I tried those today. Very interesting results! At ~5% of each, mixed in the dry, you can't see them at all. But add a little water, and the sorting is amazing; they pop right out! Red's not so good, but maybe the blue will work. But then we use blue and green dye for tracing--could be a conflict there.
Very exciting and promising.