Supporting the above:I sincerely believe that color is more of a personal confidence builder, than it's actual effect on the crappie themselves.
Nothing seems to effect the bite except having "something" moving in front of them at the correct depth & speed that they are looking for.
I've been fishing with five soft plastic lure shapes I designed or lures I modified last year, each having a unique action. All catch 5-6 species of fish including crappie.
Lure shape determines a lure's action by-design and along with a presentation, enhances that action, thereby increasing the chances of strikes one hundredfold.
I prefer subtle action soft plastics that can be worked slower than any other - even under a float - and therefore no longer care to use curl tail or boot tail (shad) lures.
Shape and lure action are two sides of the same coin that fish are sensitive to with color emphasizing both. Therefore a few colors will do the job 100 % of the time and so my preference is to use muted colors and let a lure's design speak for itself. (The colors pictured do fine in any water.)
There hasn't been a day fishing this month where I haven't caught at least 40 fish. Recently my numbers have been over 100 per outing (belt counter) and have included crappie, sun fish, yellow perch, bass and roach - all on many of the lures pictured.
Today I decided to rig a few beneath a foam float and two designs got slammed by crappie and sunfish. Jig size was important - 1/24 oz was just right. (1/32 too light, 1/16 too heavy). Which brings up jig weight being as important as shape, action and color as it pertains to lure speed and presentation.
Sorry to have expanded the original question to other factors, but as a lure maker / designer/ modifier and tester, I must in all conscience put other important considerations on the table - controversial or not.