At some point I discovered that engraving on dark paper produces different colors. Depending on which power and speed settings you use. Sometimes the paper becomes lighter, almost white, sometimes darker, towards black. I played around with it a bit.

Every colored paper reacts differently. To find out how, I made a test chart. You can download it here and try it out for yourself. By the way: These are not special papers but normal craft and drawing papers.

If you want to make a picture with two (or more) colors, you need a color separation for each color. Then place the images on different layers in xTool Creative Space and select the appropriate values for each image/layer. For example: black (power 25%, speed 50 mm/s) and white (power 25%, speed 400 mm/s) Et voilà!

You can simply leave the color separation for black as it is. The black is engraved. However, the white color separation must be inverted, i.e. a negative must be made, because the laser only wants to engrave black parts of the image. So you just make the white parts black. That's all there is to it.