Many anglers will tell you color is at the bottom of important lure characteristics. I believe color is equal, at times, to any lure characteristic or presentation. This goes for almost any type of lure. The guys who rank color low I'll bet always have a preference in certain color water or when they're attempting to match-the-hatch. I never try to match the hatch (like trout fisherman) because I usually don't know what the 'hatch' is on any particular day. Fish are opportunists and if a minnow is swimming by, close to the strike zone, it will be sucked in. If a frog then happens to make a surface commotion just after the minnow meal, it's history from the same fish or one nearby.
Quite a few anglers on other forums seem to agree on one thing. Water color and availabe light should determine what color will contrast more with a background, never less. That means the use of lighter or darker colors based on the above. Sparkle and metallic reflection should be considered light or flashy characteristics.
Worms and other bottom lures may be more effective if they contrast either subtlely or glaringly. The problem exists when fish are close to cover and look up versus down when feeding. Black or dark prey are common in nature, so a lure that splashes overhead, presents as a dark silhouette regardless of water clarity. Reaction strikes on black worms and jigs are common. Translucent colors are just as popular and are effective top to bottom, especially is they contain sparkle. Laminates also offer visual contrasts that anglers have found to be as effective as sparkle (i.e. red shad).
Are there rules for picking colors for certain situations? There may be, but in my opinion, what works on one lake or river, may not work on another on the same day. I know the color range that generally works in my local waters, which is broken down to season, water clarity, time of day, wave action, cloud cover, and the particular soft plastic I'm throwing. The must- have-colors in my box are: watermelon with red/black flake, camo, sour grape, june bug, red shad, rootbeer with green/blake flake, chartreuse- pearl, pearl, green pumpkin and black flake, chartreuse and black flake, black and blue or red flake, and copper head with blue flake.
My belief from my annual experiences is that certain colors work best with certain soft plastics at certain times of year. For example, I dyed pearl Stik-Os chartreuse, and caught fish in water warmer than 60, all year long. I caught bass and pickerel in my local pond and up north in a 7 mile-long lake that I never fished before. Watermelon and red/purple flake Stik-Os also worked very well. Pearl Stik'Os didn't work until the water started to clear a little with temps falling back into the 60's. Rootbeer and flake Senko's also started doing very well. The fish have shut off to chart. Stik-Os.
Junebug Hoo Daddys worked very well on smallmouth in my local small river, that has more brownish water but only until water temps reached 60 or above. Rootbeer and greenflake Hoo Daddys worked just as well for the whole warm-water season. In fact, I can thing of dark to light colors numbering about a dozen, that could have caught smallies almost any time of day, all season long.
Experiences help form beliefs and confidence, if only temporary, and can only offer personal guidelines as to what color to throw and when. When your basic color arsenal doesn't work, experiment. Keeping a log book has helped me not to become rigid in my beliefs about color selection and has showed me that on certain days color didn't matter and on other days, a certain colored worm caught over 10 bass in a short period of time. I even include in the log, what colors others have used on a particular day, especially the guys that came in first place.
My own rule is to never limit myself to plain black, except in small ponds or lakes that have concrete, rock, rip-rap, trees down or overhead tree branches. Black and red flake works as well. For larger waters, the above colors are my basic arsenal.
We would all like to believe (as the Color C Lector pushed) that rules can dictate color selection. Dr. Hill is only one of many con-artists to promote 'factual data' that supports predictive theories tied to a product. Use your own experiences to guide you and pay attention to what others are using. Experience is the best teacher. The more 'rules', the less fun, fascinating and mysterious, fishing is.
The pros all have color preferences. I'll bet trial and error taught them alot over the years, just as it has me and anglers I know.