You’ve all been so helpful with my questions, here’s a short tutorial on engraving mirror tiles.
I bought them from Amazon:
This photo doesn’t do the end product justice:
I set the thickness at .07 inches
and the speed/power at
The image was imported into photoshop, converted to B&W. I hit noise/reduce and then reversed it to a mirror image, then saved it as a PNG.
When I put the mirror into the Glowforge, I did it shiny side down, so I was able to engrave the back.
Next time, I’ll center it better, but it’s really stunning to look at. The tiles are cheap, and someone with little talent like me can still create a pretty sharp output.