I was looking for a thread - one the GAT had posted on - about the effectiveness of peacock herl and the color transformation that it undergoes when in the water. The green looks - to my eye - as a sort of copper/brownish color when wet. No one seems to dispute the effectiveness of the material and perhaps it is because it transforms into this "natural, very fishy" color. While looking at pictures of fish under water (bill fish, tarpon, trout) - I noticed that the fish will also show this color under certain lighting scenarios. It got me thinking - this color change may be a sort of natural phenomenon for most things wet. Maybe this explains why the herl can work so well. Just a amateur's observation.