Settings for a rubber stamp

I am looking to take a photo of myself and use the laser cutter to make a rubber stamp of my image.

Is anyone able to give me advice on what settings to use?

I am tired of signing your books for my students. So instead, I’m going to stamp a picture of my face. I lost my previous stamp, or more likely a student stole it.

I have done this in the past but when I did it, the technician at the library did it for me, and it was a very long time ago.