Unfortunatelly, my local suppliers don't sell me as a non professional user, this kind of dyes. Well I do some experimentation when I have free time with emulsions as a hobby, so I'm not in a hurry.
I remeber some simple experiments I use to do In the begining, with some vegetables juice, like carrots, red cabbage, myrtille, beet.... some of them maybe are photosensible, (evidenly ultra low sensibility). I used to extended in a paper, and put some objects up, and expose to the sun, then appears de silouette of the objects. Maybe there was some way to concentrate this colorants chemically.
Anyway you are right, a good ortochromatic its a big deal by the way.