I know that as steel (or some steel anyhow) heats, the surface changes color and if one removes the heat the color will stay on the surface. I've done this using a propane torch, but isn't easy to do in an even manner. Can anyone explain what's happening to cause this?
I've got some projects where I'd actually like to maximize and control the surface coloration. What I can do to make it as pronounced as possible? Are there different types of steel that would be more or less prone to this? Any techniques where this coloration can be more easily generated or saved? Any websites that discuss this?