The easy bit is that it is a printing plate.
That's where "easy" ends.
It is definitely NOT the sort of plate used for lithography.
The stones used were/are solid limestone and usually fairly thick, 2-4 inches.
Lithography plates are typically aluminum, with a coating on one side.
By 1923 stones for commercial lithography were less common.
What this is - Is a plate from one of the forms of typography. The suggestion that it's from either a newspaper ad of some kind or perhaps a book is a good one.
It's still a pretty cool piece, making them wasn't always cheap, which is why some old publications bragged about how many photographs either color or otherwise were included.
A bit of work should actually let the owner produce a print, maybe not a great print since the halftone screening is a pit rough, but a print.
I have a couple from one of the postcard sets, I've never printed from them, but it's possible.
Steve B
