This lens does not appear to be mounted in a shutter, and the board is not unlike one that might be fitted to an enlarger, e.g., a D2, so it may have been used for enlarging but that is hardly dispositive.
Here - https://api.offerup.com/item/detail/944259158/ -is an image of the same lens mounted in a shutter; however, that does not mean someone could not have used the lens for projection enlarging.
I have no idea why the corner of the board would be cut like that.
N. Riley
http://normanrileyphotography.com
Dimensions?
4 7/16” square
Bookmarks