This is a technical blog post on my current method of developing large format sheet film using standard 4 ( 101 mm ) inch plastic drainage pipes and stainless steel film developing tanks ( see photos above and below ). A bit of back ground, I have been developing my own film for the past 40 or more years, first with 35mm film, I have been developing sheet film of various sizes for the past 37 years or so. I have tried and used various methods, from trays to dip and dunk with film hangers, the simplest but not the easiest is the tray and shuffle method, favoured by Edward Weston and many others, I tried this for a while, but ended up scratching too many negatives. For a long period when I had a real darkroom I used sheet film hangers with tanks, they worked well, but agitation was tricky so I ended up making my own version of film hangers with wire clips attached to sheets of plastic, they worked and rarely did I have a negative come out of the SS wire clips that I made or had uneven development.
About 12 years ago I down sized my darkroom and no longer have a "real" darkroom except for my windowless bathroom, which I use for loading film into developing tanks ( all dry ) and changing film in my large format film holders (mostly 4 x 5). My film processing area is in the laundry room of my house, its small but works well, has running water etc.
I thought for a while about how to process large format sheet film in daylight tanks, I don't recall how I found the plastic drainage pipe and put two and two together, I remember have some 4 inch ( 101 mm ) plastic drainage pipe laying around the workshop from another project, lo and behold, I found the drainage pipe fit just nicely inside the round standard stainless steel developing tanks, those tanks come in various sizes in terms of length, mine are the large ones, they hold 4 rolls of 120mm medium format film, since I only had two of the big tanks I bought two more.
I cut the drainage pipe into 5 inch long lengths and drilled 1/2 inch ( 12.7 mm ) holes for the chemistry to get in and around the film, buffed off any sharp edges, I found with a slight curl of the film and enough tension that two sheets of 4 x 5 film would fit inside of each piece of drainage pipe, the problem was how could I stop the film from sliding around during development ? I solved the problem by going to a plastic store and bought some 1/8 inch thick soft plastic sheeting, these I cut into squares which are fitted in by pressure inside the cut to length plastic pipe, so they are divided, these act as a partition inside the plastic pipe, this way each sheet of film had its own separate chamber and does not move around. Each of the big stainless tanks holds two of these 5 inch long film holder pipe, so when fully loaded each tank holds 4 sheets of 4 x 5 film.
Some people might find that this method uses a lot of chemistry, but it actually works out to be quite economical. Total volume of chemistry is 1400 ( 47.3 US oz ) I am currently using Kodak HC-110 Film developer, ( the one litre size of concentrate ) at the time of this article is priced around $30 (cdn). I mix that 1:3 for my "working stock" from this I use it at 1:11 ( 117 ml of working stock to 1283 ml of water ) or ( 3.9 oz of working stock to 43.4 oz of water ) this will develop 8 sheets of 4 x 5 film, the entire 4 litres of HC-110 mixed stock will develop something like 200 to 250 sheets of 4 x 5 film or about 50 to 60 8 x 1 0 sheets. I have been using Ilford Rapid Fix which is one of the longest lasting fixers I have ever used, I would guess that it would fix something like 300 to 350 sheets of 4 x5 before becoming exhausted. My development times are 9 minutes and 30 seconds @ 20 C or 68 F.
I have four big SS tanks which I load up all at once this way I can process 16 sheets of film, I start the film processing procedure, I process just as if I was developing a bunch of rolls of 120mm film or 35mm film, I usually start with two tanks, pour in the developer , start the development timer, use a standard inversion agitation method, then once that is done, go to fix etc, once the first batch of film has completed developing I start the next two SS tanks, so by the end of an hour or so I have 16 sheets of 4 x 5 film hanging on my drying rack.
With this method I have developed up a 100 sheets in one long day, but often its more like 64 sheets , what I also do is if I come back from a trip and say have a 100 or more sheets to develop is I will develop 16 sheets a day, after work, this way by the weekend I have most of my film developed. Another handy thing I use is the Massive Dev Chart for iPod, iPhone or iPad
So how does it work?, I have using this method for over 11 years now, the developed negatives are excellent, nice even development, they look beautiful!. The plastic drainage pipe has never worn out, and even if it did all I would have to do is go and cut off another piece, drill a few holes and away I go. The big SS tanks are quite expensive new, but can be found used , they would last a life time or more for most folks. The whole system is simple and durable and can be used with out any real darkroom, only need a dark place to load the film, a film changing bag can work for that purpose. I always load my films dry and the pour in the developer through the plastic lid on top of the tank which is securely in place ( always double check ). I guess the one draw backs of this method is the tanks are heavy to lift, each tank hold about 55 oz ( 1626 ml ) of chemistry, so when loaded plus the weight of the SS tanks and plastic holds they weight 4 or 5 pounds, ( 1.8 to 2.2 kg ) a bit of a work out for sure when they have to be picked up and inverted for agitation once a minute!Also I have tried using this method for developing 5 x 7 and 8 x 10 sheet film with some modifications to the plastic drainage pipe, ( no plastic dividers ), slow to develop 8 x 10 as I can only do 4 sheets in a hour, but it gets the job done.
This is just one method, some folks reading this will have their own method, there is no right or wrong way. I hope for people wanting to learn how to develop sheet film this will give you some ideas.