lock layer makes your drawn area your only work area. It's a bit hard to explain, but try drawing a smiley face for instance on a separate layer, click 'lock layer' and change the color of your brush. Now try drawing on the lines of that smiley face: the lines will be the only thing that's affected, not the area around, so using this method, you can easily change the color of your line art (if you have your line art in one, separate layer)! This also works if you've colored, say, your character's sweater in a separate layer, and you want to change its color without using the bucket tool. I think lock layer is a handy feature
oooohhhh nooow i get it, so first color the sweater then lock it and once its locked you can recolor it and say you color outside of the lines it wont show up because it hasnt been colored on that layer? i understand what it is now thank you!
ok so when coloring the "sweater" for example, and because thats on a different layer i wont color outside the lines of that sweater? so if im correct there is 1 background layer, 1 coloring layer, 1 lineart layer that is locked? and because its locked the layder underneath you can color outside the lines? im sorry to ask sorta again im just making sure i got this right