I am tying some flies using different colors of floss. However, when they get wet, the floss changes colors (the red floss turns almost black). I had read somewhere that many of you all coat the floss to preserve the color. However, I can’t recall what you used. Any suggestions would be appreciated.
Whenever I tie a fly that has floss I coat the floss with Sally Hanson Hard as Nails finger nail polish. It gives the floss the “wet look” and makes it more durable.
All of those options will work and I urge you to try them all. Patterns that use floss or dubbing use a certain kind to obtain a certain amount of transparentcy. Coating the floss with a hard coating will not allow the water to turn the floss transparent. Using different colors of thread under the floss will give you different shades of the floss while wet. I am not familiar with the color preserver, but I imagine that it either stops colors from bleeding (quality floss shouldn’t bleed its color anyway) or it coats the thread with some kind of water proofer. Experiment and have fun.