More here
Most of the trays have the little drip corner on the bottom right, and these look like commas to me.
One of the trays belonged to Wynn Bullock, whose name I'd been trying to remember for the last week or so - his "colour abstractions" have been in my head for a while as I'm seeing their influence shine through in some stuff I'm doing at the moment.
EDIT
I originally wrote this post before I woke up fully, but the "stuff I'm doing at the moment" actually refers to the "end" photos, the offcuts from the printing machines in photolabs. The colours and sometimes even the forms have pretty striking similarities to Wynn Bullock's abstractions.
