The instrument described here is a simple portable device that quickly produces accurate and permanent 2¼" x 3¼" photographic prints of bathythermograph data, both smoked slide and calibration grid being photographed simultaneously….
Schaniel, Carl L.. 1954. "A camera for photographing bathythermograph slides." Journal of Marine Research 12, (3). https://elischolar.library.yale.edu/journal_of_marine_research/799