Anyone recall reading about the very difficult trout that was only taken after the fly was attached to a tippet constructed of black thread? I think it was written by Schwiebert,...and possibly told in Trout. As I remember, the lesson relayed was that it wasn't so much the color of the tippet or possibly the size of the tippet that mattered as much in this scenario as it was the thread's incredibly limp quality which allowed for a better presentation.

Since I only catch the most suicidal trout, any testing of this theory done by me would be pointless.