That article has some great info. I have always had my doubts about fish seeing colors, but the article says that they see colors in the yellow to green range better. That makes more sense. I know there are several blue flies on the market and I know I have never seen blue bugs or eggs. One thing I would have to disagree with is that when a fish slams a fly it does not think it is food. Caddis patterns and other emergers are slammed on a regular basis. Caddis emerge quickly and the fish slam them. Well, off to the creek to terrorize some of those smart fish.

Some generalizations in the article may relate more to lakes than Putah, but anyone wearing white hats/shirts or using a yellow flyline and standing within 20 feet of a trout waving a long stick or moving around in the water grinding stones together while casting may be putting themselves at a disadvantage (unless, of course, you are sneaking up behind them from downstream in fast water).