by Tuike » Fri Oct 28, 2011 6:10 am
Lock alpha locks transparent pixels. It will not let you erase or add anything, only colour over the area you've already made. So if you use it on empty layer, you can't do anything, and if you use it in a layer that's completely filled, it has no effect other than not letting you erase.
First make an area for your colouring, then click lock alpha. Now you won't go out of the area you made. :] So, firstly, get sure that you're using transparent layers (transparency is shown with checkpattern), and make separate layers for lines and colouring. If you need more help with getting the layer order and stuff right, let me know, I have a little tutorial made. ^^