I also had trouble with engraving mirrors. Considering most mirrors are silver with a copper backing ( two, supper reflective materials), and was amazed at how much energy it took to create. I’ve also had mirrors crack on me, due to the excessive heat. I managed to get this one done for my nephew.
That looks great! Mirrors can be difficult but once you figure out the power required, it is possible to get some excellent detail on them (like you did).
Also, good job on the photograph, the most difficult problem I have had so far is figuring out how to take a decent picture of the finished mirror.
Did you paint the back of the mirror after engraving?
Yes, once the mirror was finished ( I held my breath until the very last scan line was done! ), I spray painted the back with black enamel paint.
One of things I had to learn was how to process the image so that it would be better represented on the mirror. It looks a little strange on the computer screen, but the results on the mirror come out great.
Fortunately, I have high ceilings in my house, allowing my to get a picture of the mirror without fixtures hanging from the ceiling getting in the reflection.