From back in young childhood I remember catching lots of pale blue crawdads that had recently molted. Also, While doing some shallow diving I have seen crawdads in and around shale outcrops that have dark blue and purple streaks, as well as black backs. Now as for color mattering, its probably a visibilty issue, when color doesnt seem to matter much...they just have to be able to see it. Now when color seems to matter its probably a function of a concentration of 1 type of forage in an area. Example: May tourney post spawners would only eat a light weight green pumpkin jig with matching trailer on heavy mono or FC for a super slow fall...took me 3 days to figure it out. And it had to have a rubber skirt, and be a certain lighter shade of green pumpkin to be the most effective. After a few of the fish I caught puked up 3-6inch blue gills that were exactly that color I began to realize that the Bream color was very important. I experimented with some other colors in likely spots and got nothing or maybe small fish, but it was probably a 10:1 ratio for any other color against the light green pumpkin jig. In the same spots after trying alternate colors, on the very next cast or a couple of casts later, I would produce a fish on the green pumpkin...color mattered. I got on a good vibe bite another time but they would only hit a vibe with the green scale pattern overlaid on a black back...the black back alone would get you nothing, and a vibe is obviously a reaction bite. Another instance was a very productive deep crankin bite I was on, was extremely good on a dark blue green back DD22 under semi low light conditions...any other color would leave you empty handed...and I tried other colors. Now when a cloud rolled in, They would quit the Smokey joe, but would absolutley crush a a green joe (same thing but with a chart line just under the blue green back). Color mattered. On the other hand, I found post spawners hangin right off the bank 1 day and absolutley smoked em with senkos. I started out with june bug, but ran out after about an hour. I changed to white and never skipped a beat. I started changin up just to see, and caught fish on ever color senko I had when rigged weightless, but not a single nibble on a t-rigged or shakey head, or drop shot. That instance was purely a technique deal, but I had good water clarity and anyting that was visible and presented a certain way got bit. Tim Horton commented that he has never been too hung up on color, if your around the fish and they are actively feeding, the right presentation will get you bit every time. This is probably correct for the most part, but I think color can be the difference between a good bite and a great day.