An easy way to remember the order in which colors turn to gray or black as a lure drops in the water column is to think of an angler named "ROY G. BIV", who fishes the spectrum according to depth. Of course, ROY G. BIV stands for red, orange, yellow, blue, indigo, and violet.

I believe that the reason that steelhead and trout frequently bite red or pink lures, roe, or plastic worms is that we often fish for them in the top 15 feet, where red has not washed out much yet.

I also like the theory that calls for lures with dark undersides for fish that approach from below (to contrast with the sky as the fish looks up) and lures with light topsides for fish that attack from above (to contrast with the dark bottom).

I think that we may make too much of the change in color/lightness of a lure with increasing depth. Does it really matter that the lure looks different at different depths? What really matters is that that lure at a given depth looks like what the fish are feeding on at the depth or what the the fish will attack as an intruder at that depth. Therefore, "match the hatch" is a good rule that goes far beyond fly fishing. For example, rockfish, lings, and salmon will bite bright chrome jigs and light anchovy/sardine color swimbaits, etc. at great depths although such lures do not look bright at great depths. They likely bite because these lures look like whatever anchovies/sardines look like at those depths.

Bob