076 Edge extension

- [Instructor] Hi, this is Steve Wright…welcoming you to this week's Nuke Nugget,…fixing discolored edges with edge extension.…We often get discolored edges with our key,…so here's a nifty trick…that literally trims away the bad edges…and replaces them with good edge pixels.…So here we have our blue screen,…and I pulled a basic key with keylight.…And as you can see, we have some nasty, little edges here,…and dark pixels, not very nice, not very pretty.…So the basic concept is,…we'll do an unpremultiply on the output,…and we're going to trim away the bad pixels,…then replace them with good pixels,…and do our comp with those.…

So let's see the workflow.…Starting back up here with the keylight node,…of course we have our key right here in the alpha channel.…We do an unpremult,…you can actually see the discolored edge pixels here.…This is what you get after they've been…spill suppressed inside the keylight node.…Okay, so let's push in and see what's going on here.…Alright, so from the unpremultiplied version,…we go to an erode node,…