Tuesday, January 17, 2023

Hangers and Tanks

I get the impression that most people do not understand the logistics of processing sheet film.  I thought I would offer a brief explanation.
I made seven tanks out of plastic sheet back when I owned my skylight company.  I also made a couple of film washers... one for 4" x 5" negatives and a second for 8" x 10" negatives.  In fact shortly before I retired I also made a batch of larger tanks for developing 8" x 10" negatives.
I used standard stainless steel hangers.  Each one of these holds one 4" x 5" negative for processing.  My tanks are wide enough to accept up to seven of these hangers.  The tanks each hold 2L of solution.  The seven tanks are for a water presoak, developer, stop bath, fixer, rinse, Hypo clearing agent and a final water bath.
It is quite the operation to develop a batch of 20 sheets of film...!  I start by turning off the lights, and inserting seven sheets of film into the first batch of holders.  These hit the water pre-soak to soften the emulsion and get the film up to process temperature.  I set my glow-in-the-dark timer to the appropriate development time and then move the hangers over to the second tank, which contains the developer.  Agitation is typically once per minute, so while this is going on, I load the next seven sheets into seven more film holders and start them in the pre-soak.  Once development of the first seven is complete, I move these over to the stop bath, where they go through a wash with agitation, for about a minute.  As soon as this is completed, this first batch of seven moves on to the fixer.  While the fixer is ongoing, I move the second batch to the developer, and reset the timer.  As development of the second batch and fixing of the first batch proceed, I load a third batch of film into the last six holders.  This all progresses in total darkness.  As fixing is completed, those holders move over to a brief water rinse and on into a hypo clearing bath.  Once the third batch has completed fixing, I can turn the room lights back on.  Then the rinsing and hypo clear are completed for all three batches, and the film moves on to the washer.  My custom made film washer is able to wash 20 sheets of film.  I wash by soaking the film for at least 24 hours, during which I change the water at least ten times.  At the end of the wash I add some Photo Flo, which is a wash agent that helps to remove water spots and mineral deposits.  Once the wash is complete, the negatives are individually rinsed with a mist of distilled water, and hung up to dry in my drying cabinet.
I generally save up batches of exposed film until I have at least 20 sheets that require the same development.  As I shoot so many different kinds of film, and different developers and times are required, I usually have a significant backlog of film that requires processing.
This all seems a little confusing and overwhelming, but over time I have become fairly competent at keeping track of this and processing accurately, in total darkness.  Its all rather surprising considering I am very disorganized in life, and walking and chewing gum at the same time proves challenging...!






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