A visible light laser is not going to work on something you can see through. The materials must block/absorb the energy of the laser beam… if it just passes through, it can’t damage the material. That is why you are using the dark paper…
I’ve seen many people use tempera paint, black markers, various lubricants and many other things to change how the laser effects the material.
There is also the Norton White Tile method that molecularly bonds TiO2 to glass and other materials… Some of us use it with water and lase it. The NTM usually uses paint, that you have to get off after you lase it…
@Bulldog does incredibly masterful work with this technique… lately he’s applied it to his new fiber laser…
Good luck
