Identifying colours using GIMP

Often we find a need to identify colours on the screen. There are lots of utilities and fancy tools out there, even web based ones, but I tend to use GIMP as I have it installed already. It's a general purpose image editing tool along the lines of Adobe Photoshop, plus it's open source, so head over and get it now.

What is z-buffering?

Z-buffering, also known as depth buffering, is a computer graphics technique used to determine what objects should ultimately appear on the screen and be visible to the user in the final render.