I use a gas torch to heat the titanium and to get all the different colors. You get the brightest colors on a high polished piece of titanium. When you heat and get the colors in the titanium it is only in the top layer of the metal, so the colors will wear off over time. It is like a plating.
When heating the titanium use a smaller flame on the torch and do it bit by bit to control the colors. The colors will change quickly. Once burning the titanium, as it progresses, you will start getting colors from gold, bronze, purple, dark blue, light blue, green and pink.
I prefer heat treating the thinner sheet in the titanium (0.7mm = 0.028 inches), because it is easier to get great colors and the colors won’t fade out if you keep heat treating it. Especially when you reach the last colors green and pink, try to heat it with the gas flame a lot till the metal gets all red, then stop. Now you will have amazing bright pinks and greens.
I have also tried to sand off the colors of the heat treated titanium and heat treat it again, but I couldn’t get much color the second time I burned it.
You can experiment in doing textures, then burning and sanding off so you have colors left in the textures. There are so many exiting ways you can work with the titanium. Just try it out for yourself!