When I selected the green for the stripes, I just grabbed a piece that felt large enough, out of my stash. It wasn't until I actually picked it up to use, that I realized it had been used to try out some fish printing. This was several years ago and, yes, I used a real fish,--a Lake Trout. The process resulted in three pieces, long since gone to new homes, but I had totally forgotten this . If memory serves me, this means that the colour is hand painted, rather than dyed.
I'll let you know how it goes.