Read an article a year or so ago, bout tying a small box of all white flies and carrying markers to match the hatch. The point of the article was you could arrive anywhere and come close to matching the hatch with out carrying many flies.
At the time I thought his was a great Idea and had Denny at Conranch send me a White Cape, which I have never done anything with. Today I saw a post by Normand (I think) re using markers to make white thread any color you want. And it got me thinking about this article.

Anyone use markers to color flies???

Eric