Dyes

is there a "best" place to go and farm rare dyes, or is it all just random?

Drops are affected by the area you are in, any enemy can drop a black dye, but a monster from FoW has more chances of dropping one than a hulking stone elemental in post searing Ascalon.

Says who tijo? Black Dyes, heck, ANY dyes are core items and can drop anywhere from any monster. If you could argue that ANY location in the game has the highest percentage, it should be Pre-Searing Ascalon because there are slightly fewer item types that would load there. (core items only, mostly low-value items, etc)

What Mournblade said... The most dyes come from whichever things you can kill more of, faster.

Presearing is the best place for dye, but the Gates of Kryta (I may have spelled it wrong the mission that takes you to Lions Arch) for some reason dyes drop alot for me. (If you are farming it solo) As said before alll locations can and will drop dye.