ORIGINAL: JeramyK
I found this on Carolina Archery Products website.
White vanes are the softest regardless of the manufacturer or material. This is because it takes a lot of dye to produce the white color and the dye weakens the vane. You will also notice that white vanes get discolored faster than other vanes.
Taken from this link :
http://www.carolinaarcheryprod.com/fletch_choice.htm
Now thats interesting.. I never new that...