Processing Tanks ~ Entire & Utter History

Kodak~TankAt first films were usually see-sawed in dishes of chemicals, but this was hardly ideal, and manufacturers sought ways to make home processing easier. In 1910 the well heeled chappie in spats would have been investing in a sophisticated Kodak Brownie Film Tank system. The Model B, shown here had 3 basic components, the film winding box, the stainless-steel tank and the spiral assembly, or drum. The box was a loading system for the drum – the film was wound onto this simultaneously with a celluloid spacer; this allowed enough space for solutions to flow around the film. After the loading operation the film coiled up inside the drum was transferred to the tank. Ingenious but complicated, expensive, poor on agitation and some parts of the operations needed to be done in a darkroom.

The Kodak tank was difficult to improve on because it had to cope with a very wide range of different roll film formats – there were literally dozens in the early 20’th century. As the range was rationalised it became more of an option to come up with specialised tanks adjustable to a smaller range of formats.

Johnsons~TankThe arrival of thermosetting plastics opened up new avenues, and the first plastic to market was a slightly smelly brittle material ‘Bakelite’, which came into wide use in the 1920’s, an example shown here being a Johnson’s 35mm. The main evolutionary jump was that a moulded spiral could be used, and the film wound directly into it, by pushing it in from the outside of the reel.
Tank~SpacerThe wound-up spacer idea never really vanished though, and kept cropping up, shown here in a German tank from maybe the 1950’s.


MorseDealing with longer lengths of fim on a small scale, and in the field needed an alternative to the grooved spiral, and the rewind tank was the answer. The film is wound onto one reel – the developer then poured in, and then wound using the handle onto the opposite spool. And then back again, repeating the process a number of times. It’s not without problems, the agitation is less than ideal and the film is more likely to suffer mechanical damage, but it does the job. Good if you want to process, say, 100 feet of cine film – look out for one of these ‘Morse’ US made bakelite tanks. An ingenious little window at the front allows the fogging exposure that might be needed for reversal processing.

Pat~Tank~earlyDonald Paterson was one of those new age people whose multiple accomplishments seem so irritating to us today, being a qualified lawyer and dental surgeon, as well as an avid photographer. On safari he observed a snake swallowing a rabbit, and realised the one way traction of the teeth of the snake could be employed to push film into a spiral. The distributors R F Hunter took up the idea, and a range of tanks were launched in 1948.
The spiral used ‘snake tooth’ projections at the entrance of the spiral to snare the sprockets on 35mm film and push the film in – this wasn’t much use with roll film, so the Mark 3 version substituted stainless steel ball bearings, which worked with all formats.

RondinaxAgfa-Gevaert is largely a memory now, but this German photo giant produced some very inno- vative products, not least the ‘Rondinax’ tank. This took some of the ideas of the Kodak 1907 model and rolled them up into one unit, in which a film could be loaded and processed in a combined tank & loader, the big selling point being all operations were IN DAYLIGHT. It even had its own built in thermometer. As well as the popular 35mm there was also a 120 version, more rare which might have something to do with it’s unpredictability. No longer made, but if you find a working Rondinax cheap on Ebay, grab it.

GEPE~5x4~smThere have been many small scale 5×4” processing tanks but a lot of them had problems in applying adequate agitation. The GEPE tank is still very popular and does a good job if used properly. Supplied like an Airfix kit, the hanger holds 6 sheets.
For processing larger quantities, deep tanks and stainless-steel hangers are still the answer.


SS~spiralsProfessional film processing is highly reliant on stainless steel gear, and it’s worth getting to grips with it on the smaller scale having cut one’s teeth with plastic tanks. Secondhand tanks & spirals can often be obtained at low prices, and looked after they will last for ever.

The main difference from the Paterson style plastic spiral is that loading is from the centre outwards – this can be tricky when first attempt- ed but gets easy with a bit of practice. A big plus is that there is very little carry-over of solu- tion from one bath to the next, and consider- able heat can be used to force-dry wet stainless steel equipment. The British manufacturer ‘Hewes’ still makes a wide range of formats for different widths & lengths of film; illustrated, 70mm spool for bulk lengths against a standard 120 spiral.

HP5_72An interesting divertissement in stainless steel history was the 72 exposure tank & spiral marketed by Ilford for their HP5 72 exposure autowinder film (left) in the late 1970’s.
The film itself was pulled early due to technical reasons;
1] To get 72 exposures into the cassette a thin polyester film base was used, which was so tough it was virtually unbreakable. Consequently if a jam occurred, instead of tearing like acetate would, the likely result was gears stripping in the camera.
2] Camera film counters only go up to 36, after that it was guesswork.
3] The polyester base curled like a watch-spring and was very irritating to work with.

So the film was abandoned by Ilford early in its life. This left a mountain of the beautifully made tanks which were sold for a pittance. Look out for them, there’s still a lot of them out there.

Pat~Tank~above60 years on the Paterson system of plastic tank & spiral has been refined several times, reflecting changes in available raw plastic materials as well as design innovations. It’s been copied, of course, and the best compatible clone is probably the one marketed by Kaiser.
A long journey in lateral thinking from the early Kodak tank.