Quote (lucero @ Sun, Aug 16 2009, 01:13pm)
channels only work if there is a high contrast
but if you make sigs you can work with the stock though
you choose whatever channel has the highest contrast and then multiply it through image calculations
if the stock isn't already on a one color background, then you brush around it to make it one color which makes it easier to work with channels
a lot of professional photo shoots have models on a plain background so it's usually easy to render... there are obviously varying circumstances which need adjustments
but rendering hair is by far easiest in channels