Painting and editing the third-pass mask

In this exercise, we're going to try our hand at selecting these hairs in the…lower left region of the image, and we're also going to try to build out some of…the hairs in the lower right region and we'll do so by building a third pass…mask from the blue channel.…I've saved my progress as Combined calculations.psd dfound inside the 04_tough folder.…The reason we're going to work from the blue channel is we've pretty much…exhausted our calculation options here.…You could try some others if you like but it seems to me that only the blue…channel provides any hope for this lower left region, because after all if you…zoom-in on it and take a close look you'll see that the dark areas inside the…channel are actually representative of the background and the bright areas, the…relatively bright areas that is are representative of the actual hair.…

Now that's not always the case of course.…Once we start getting into some of these regions, the hair ends up darkening up…and we've got some real problems right here, we are going to pretty much build…