Photographing Japanese ceramic marks to being out the writing

For thin walled porcelain use a flashlight from the inside out

 

Rub white starch into the mark

Press silly putty or similar into the mark, reverse image through photo editing

Rub graphite over the mark avoiding falling into the mark

Flashlight directed to the side 

 

Electrical tape pressed over the mark, reverse editing

Flashlight to the side on graphite smudge over mark

Photograph in a light box

Photograph on a tilt