HI Folks, this was a first time lithophane for me, and it worked well, I reckon.
(The 2nd time one had a few problems though...!)
It was done for a Christmas present for an uncle who's 93 years old. It's of a photo of his parents in about 1946, with a grandson of theirs.
It was done in 3mm opal perspex-type stuff whose name I've suddenly forgotten, and is 21 x 29 cm.
The three photos show it close-up half roughed with a 1/8 ballnose endmill & half cleaned up with the 1/16" one, then the finished product, then the finished product held up to the light outside, so it doesn't look like a negative anymore.