It's been quite a good day. My laser actually appears to be doing more-or-less what I want it to with the stuff I've tried, and I managed to burn an image and cut in one operation, which is a step forward. Six bits too. Heh.
So. We wandered over to the beach for a quick drink to celebrate my wife's birthday and to watch the eclipse (the moon popped out from behind the cloud bank 4 minutes after the eclipse had finished....b***ard). Also, while I was there, I picked up some smooth flat stones to have a go at with the laser. My daughter picked up a tiny stone and asked if I could engrave something on it.
"Dunno.", says I, smug from the novel feeling of the laser doing something close to what I wanted it to, "Probably. What would you like?"
"The Mona Lisa".
"Ah".
The conversation developed, as these things do, and pretty soon there was €5 riding on the outcome. Now €5 pocket money is pretty serious money; and my daughter might miss the money too. I think it's possible. My machine does, after all say 1000 dpi in the instructions.
This is the stone. It's igneous:
So I got my calipers out and worked out that at a theoretical 1000 dpi, that'd give me 276 pixels on the long edge of the image of the Mona Lisa (218k so linked) that I bagged from Google image search. After some fluffing (consisting mostly of running it through Photoshop's 'photocopy' filter (which has been giving me some encouraging results), I got this:
...which if I can bang down on stone in 1000 dpi should be as accurate a representation as humanly possible with the tools allowed.
I plan to use 100% speed, and gradually ease up on the power. I've flattened the stone on both sides with another stone (and olive oil to polish, to the disgust of my wife), and all is theoretically good.
But I only get one go at it. I'm fairly sure that not many of you have prior experience of the situation, but has anyone had a go at stone for high-resolution? Or stone at all, for that matter? There's probably a reason why this is impossible, but I'm going to try it anyway. Any advice?