Here are some portraits I recently made on Ilford F.P.4. dry glass plates which expired circa 1950. The box doesn’t have a visible expiry date that I can find but the label design (see below) was dated by Nicholas Middleton who has done some research about it. His excellent photo blog contains a wealth of information about various old film stocks, cameras and glass plates he has tested. Following his advice I rated these glass plates at ISO 5 which gave me an exposure time of approximately 2 seconds in shade. The Ross reflex camera I used has been serviced and inside is a date of manufacture from 1915 written in pencil. The camera is in excellent condition considering it’s over 109 years old. I still have two more plates to develop and six left to use.
[Tech info:] Ross reflex, Zeiss 11.5 inch f6.3 lens, Ilford F.P.4. glass plates @ ISO 5, developed in Rodinal 1+100 for 1 hour semi-stand (slow agitations at 30 mins).