I recently obtained this rather excellent piece of 1970’s-80’s darkroom machinery. It’s a mains powered automatic processor for film and paper. It’s particular benefit is for color processes, RA4, C-41 (CN-16), E-6 and ECN-II. It can also be used with some black and white chemistry to make results more reproducible, as well as more cost-effective. It’s those last two, ECN-II and a specific black and white process that were my excuse to buy a Jobo. ECN-II is a color negative process used for motion picture principal photography, the use of Cine cameras to capture an initial image on set. These are the most modern color films available and can produce stunning results in a stills camera, though one major and one minor incompatibility in the processing prevent them being developed by a normal color photo lab. Similarly, tabular grain films such as Ilford Delta, Fuji Acros and Kodak T-Max are the most modern monochrome films on the market. Their unique grain structure makes them much harder to develop to a satisfactory standard to normal processing, and newcomers are often disappointed by the results returned from a pro-lab, or developed in a common developer like HC-110. Unfortunately, the ‘correct’ developer, Ilfotec DD-X is very expensive when used in normal hand development.
A rotary processor is the solution to this, allowing the temperature stability and constant agitation necessary for color films, while allowing smaller volumes and more dilute developer for T-grain films. The CPA is one of Jobo’s earliest developers, but still provides excellent service, including some handy features that are missing from the more common CPE series. Because these machines were made around 1980, the manual is a hard-to-find item. As such, this is an attempt to create a short ‘experienced-based’ user manual for this cheap and functional processor.
Accordingly, this article may be updated at a later date, should I get any feedback or corrections.
The specifications of Jobo CPA.
- Rotary processor suitable for up to 1000ml of developer, for up to 10 rolls of 135, 12 rolls of 120 or 12 sheets of 5×4 at a time. Alternatively it can simultaneously process up to 8 sheets of 13cmx18cm paper, through to 1 sheet of 40cmx50cm paper.
- Compatible with the System 1000, System 2000, System 1500 and System 2500 tanks up to the 1000ml capacity limit.
- Analogue control of temperature with integrated thermostat.
- Auto-reversing motor drive with two speeds: 15rpm and 70rpm. (Approx.)
- Built-in circulation pump to maintain an even temperature over the development bath.
- Not compatible with Jobo Lift for automatic chemical changing. (CPA2/CPP2/CPE2 or later required.)
- No external hookup for cold water feed or drain. (CPP series required for these features.)
The big bonus then, of the CPA is that it supports ultra-large-format film and paper, as well as many rolls of film at the same time – the CPE2 by contrast, is limited to a maximum of five rolls due to the capacity of the motor being lower (600ml). The biggest loss, is the option to use a Jobo lift. The advertising claims this can make processing more accurate by automatically draining chemicals, and allowing quick refilling through the lift mechanism – no need to remove the tank from the processor. In practice, no process needs to be accurate to the second, so the biggest bonus is from the reduced amount of manual work involved. This can be helpful in a pro lab, but is not so critical for home use, especially since the Jobo uses around a third less fluid at a time, compared to standalone tanks like the Patterson Super System 4.
Getting started: The shopping list.
You will need:
- A Jobo CPA. There are a few things to check when buying a processor, especially since at this point, many people buying it will be several years younger than their ‘new’ acquisition. Firstly, there must be no damage to the housing of the processor, that would allow water to leak through. Secondly, check that the rotation and pump motors do their thing, and that the thermostat and heater are working correctly. All this should be done with the troughs full, and the appropriate amount of ‘chemicals’ (just use water) in a tank. Finally, you should check that the three-pronged rotation sensor behind the magnet drive is intact, and that the processor reverses correctly every second rotation. Buying from a dealer can save you quite a lot of time!
- A film or paper tank. Each tank will need the matching core for light tightness, and to prevent rotation of the reels. The Jobo CPA requires tanks with a magnet on the base to attach to the drive shaft. Jobo tanks are labelled with the required solution volume, so check to make sure it does not exceed the limit of your processor motor! (Again, for the CPA this is 1000ml.)
- For more information on selecting a tank, I’ve written a comprehensive introduction to Jobo tank compatibility that lists all compatible film tanks.
- Suitable bottles or graduates. Jobo sells some specific to their use, but if your processor does not have the ‘frame’ for holding these straight, other brands’ items may well work fine. Conveniently, the 1L Ilfotec DD-X bottle is the perfect size for Jobo processor bottle slots – hoard them after use!
- Jobo reels to match your tank and core. These are specific to each type of tank: System 2000 use 2001 and 2004 reels, plus 2021 for 5×4. For System 2500 tanks, you will need 2502 reels (135/120/220) or 2509N reels (5×4). System 1000 and System 1500 can share the current-production 1501 reels.
- Appropriate chemicals. For color processing, a standard RA4, C-41, E-6 or ECN-II ‘home’ or ‘press’ kit is ideal. For black and white, only low-acutance developers are typically used, because the constant agitation will increase this. DD-X is an ideal rotary developer for tabular grain film. Most cine film was designed to be developed in continuous agitation, and D76 (ID-11) works excellently for classic grain film in a rotary processor for this reason.
- Lots of water, a mains extension lead, and a good circuit breaker. You’re mixing mains voltage with a very wet environment, and appropriate safety precautions must be taken.
Setting up the processor.
For a Jobo CPA processor, between 15L and 19L of water should be deposited into the trough. If you are warming Jobo bottles and graduates in the tempering bath, Jeroen Bouman reports that 12L is sufficient, as some water is displaced by the containers. This is only a thermal consistency medium and therefore does not need to be distilled or processed, though low-salt water may prolong the life of the heating element and pump by preventing limescale. The level of the deep trough should be just above the level of the upper trough’s overflow.
There are three controls on the CPA panel. From left to right: The master power switch, which activates the heater and the trough circulation pump. The temperature dial, which controls the temperature of the water bath. And the rotation switch, with (again, left to right) slow, off and fast rotation. When warming up the processor, the master power switch should be On, the temperature should be set as required and the rotation switch should be Off.
As the CPA does not use the calibrated digital thermostat of the CPP-2 and CPP-3, the temperature of the dial should be calibrated to a thermometer in a graduate of still fluid, before using the processor. The processor will take between one and two hours to reach temperature for a color process, so should be powered on and set to temperature well before processing is required. If a fast warm up is required, the trough can manually be brought to temperature by filling it partially or completely with pre-warmed water, though this should never be above 50C and may have deleterious effects on the lifespan of the machine if done regularly, as it introduces a sudden thermal gradient in the materials of the processor.
Developing film.
Jobo reels and tanks operate similarly to the common Paterson tanks used in manual processing, and should be loaded accordingly. As with Paterson equipment, the wide end of the core should be at the opposite end of the tank to the lid. The lid must be screwed on firmly but not overtightened, and once on, acts as an effective light seal. The rubber cap can then be removed when necessary to introduce or drain chemistry. One important difference between Jobo and Paterson reels is that they must be tight on the core, rather than free to spin. This ensures that the reels rotate properly in and out of the solution and prevent uneven development. This is why the cores, reels and tanks must all match.
Once the tank is loaded, and the processor is brought to temperature, add the chemistry through the light-safe funnel at the top of the tank, put the cap on and attach it to the drive shaft using the magnet on the base. Then set the rotation switch to ‘fast’ (position II) and time the process in your normal method. When the process time is complete, set the rotation switch to ‘off’ (Position 0), remove the tank and drain the chemistry into safe storage/recycling containers as per hand processing. It is best to stop the tank mid-rotation-cycle as this reduces the chance of damaging the reversing sensor while removing or reinserting the tank. Once all processes have been completed, you can turn the master power Off and allow the machine to cool.
The processor was designed to leave the tempering fluid in the processor tray when not in use. Products such as the discontinued Ilford BIOCLEAN prevented growth of organic fouling. I have yet to find an effective substitute, so periodically draining and washing the tempering bath is recommended.
Rotary development times and dilutions.
Rotary processors constantly agitate film during development, similarly to a commercial linear processor, as you would find developing C41 in a drugstore. While this is the standard process for color film, this is different from the typical agitation model of black and white film and developer. As such, using a Jobo for mono film will typically exaggerate the highlights and reduce shadow detail, particularly compared to stand development. Development times will also tend to be reduced, Ilford recommends using a 15% reduction from it’s normal DD-X 1+4 development times. Other developers and dilutions may vary wildly, hence a Jobo lends itself to a photographer who keeps a certain consistency of film and developer choice, at least when using monochrome film. The temperature control also enables convenient processing at 24C instead of 20C, which can greatly reduce process times – especially when pushing several stops, or diluting chemistry.
From the research I’ve done so far (I will continue to test), DD-X has a ‘per-roll-minimum’ of approx 12.5ml of concentrate for 35mm film. The Jobo System 2000 tanks use around 200ml of solution per film for 35mm. Combined with the continuous agitation and higher process temperature, this makes 1+9 development quite practical, allowing the use of 20ml/film, or 100ml for a full tank. This gives a total of 50 rolls of film per 1L bottle, or about 3 times the price of developing film in Rodinal at normal dilution. Compared to 6 times the price at 1+4, or a little less than 10 times the price when developing at 1+4 in a Paterson tank, this can make shooting T-grain film quite a lot less painful. Conceivably, it’s possible to use the ‘per-roll-minimum’ of DD-X and develop at 1+15 for maximum economy, as people use the ‘3.2ml’ value for Rodinal stand processing. Without having made any tests on this however, I would not encourage anyone to actually try it, except as an experiment.
Developing paper.
This section is a stub! I have yet to develop any paper in my Jobo, whether monochrome or color. I’ll update when I do!
Rotation speed, why always fast?
When originally designed, Jobo intended that the processor be set to a ‘slow’ mode for film developing, and a fast mode for paper developing. It was believed that this would yield better results with those mediums. Over the next few years of end-user testing, it was quickly found that pretty much all processes came out better with the faster rotation setting, and some later models of processor are designed with a single-speed rotation. The higher speed of the CPA is the same as has been kept for later models, and can basically just be always used. The slow mode can be ignored.
To do list!
So far, I’ve only processed T-Grain film with my Jobo. My next step is to pick up a color processing kit and give that a try – it’s the main reason I bought the processor, so is an important step. I’m anticipating that being sometime next month, so I’ll update this once I’ve given it a few goes.
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