I have dyed materials for over 40 years and yes it does matter at times. I also dyed for a large Fly Company for over 9 years so I have done a lot of it. I kept a log book so I knew what was going on. With out it I could not have remembered some of the way's of doing some of the dying. Heck I have dyed as many as 100 capes at a time.

As far as the fish caring about the color you bet they do. Just depends on were you are fishing and what for. I have seen were it mattered on spring creeks to the point of not catching a fish at all. I have also seen it matter in saltwater.

I just dyed some calftails for a local shop. So I still do it some. In fact I have clients across the country that I dye somethings for each year. Seems they can't get the color they need anyplace else. So I say YES color does matter at times. And at times it dosen't seem to. Just depends on were you are and what you are fishing for and how much experence you have in fly fishing? Ron