JOBO CPE 2 plus PROCESSING UNIT

By Bill Reid (Area 20)

Recently I had the most interesting bargain of a Jobo Processing unit. Over these years I have used a combination of tempering baths. One home made by Bob lewis, consisting of a kettle heating element combined with a heat probe to control temperature, and a `paddle` connected to a record player motor for water circulation. This has been an excellent unit giving consistent results.

The second unit was simply a washing up basin with a UNO Electronic thermostatic heater with a fish tank water pump for water circulation. This has also given sterling service over ten years and more.

Both these units required a number of mains leads trailing around the processing area. However the Jobo Processing Unit is, as the name implies, a complete unit requiring only one mains lead. The heating element covers the whole of the water bath area and doesn`t require water circulation. It is ideal for three bath kits as it holds three plastic bottles for 300-600ml sizes. Two Jobo liquid thermometers. one fixed to check the water bath, and the other (Loose) to check the bottles takes care of that department. They are very accurate and designed so as to float in the liquid so that the reading area is always seen.

A motor turns the developing tank, first in one direction and then the other giving automatic agitation. All you need do is watch the timer. The Tank has a `magnetic` base which fits onto the motorised spindle on the side of the water bath.

There are three rotary switches on the control panel, Main Switch, Temperature control, from 40C-50C, and the third to turn on the motor to agitate the tank. It is as simple as that.

Once the tank is filled with water and the chemical bottles are placed in the `wells`, switch on the mains and within 40-45 minutes the bottles have settled at 38C. Depending on the outside temperature, and/or if you have a heated room, you will have to `tweek` the temperature control to get the bottles to settle at exactly 38C. 39C to 40C should be acceptable.

ECONOMIC PROCESSING

The tank looks small compared to the Paterson tanks that I have always used, and the base is a little heavy, having the metal base. Likewise a bit of re-thinking is required as I have always used 300ml of chemicals for a single film and 600ml for the double spiral tank. Because the Jobo tank lays on its side you only require 240mls of chemicals for two films. You could actually load two films, back-to-back and process up to four films at the same time. I haven`t tried this so far, but know that others have done so with excellent results.

The whole system is so simple that it can fool you into some complacency. I don`t have an alarm timer and during the Colour Development stage my mind wondered and I actually gave a minute in the colour developer. An Alarm would help here. Normally I would have to watch for every 15-20 seconds to give inversion agitation. The tank lies in a very shallow piece of water, but the agitation movement acts as a `water` blanket and keeps the temperature inside quite constant. I gave the tank & film 5 minutes agitation before starting the first development stage as a pre-heat.

Another worry was that you pour in the chemicals and there is a short delay before you fit the tank to the agitator and switch on. However, again, this doesn`t appear to cause any problems and there was no sign of `streaking`. The other two stages that concerned me were the Reversal and Conditioner, which require only an initial 15 second agitation then left standing for the remainder of the time. With only enough chemicals to cover the film while laying sideways I wondered if this could cause trouble, so I simply filled these two stages with 300ml of the chemicals, and gave manual agitation for the 15 secs. then left standing for the remainder. According to Rita Pearle simply turning the tank by hand every 15-20 seconds with the normal amount of chemicals does the job.

So how did my first film go? My initial mistake was forgetting to aerate the Bleach bath. The film came out looking very `grey` with just a ghost of the image on the emulsion. I had to aerate the bleach for 30 minutes and put the film through the bleach and fixer stages a second time and that put things right. However it was then obvious that I had the dratted `tobacco` effect once again. This time it was very drastic, every shadow was as red as beetroot. This at least eliminated my Paterson tank(s) as the culprit. As the two developers and the bleach & fixer had done their jobs, this left the `Reversal` bath as the culprit, which of course, is the bath I have long suspected in creating this problem.

With another film to process what was I to do? The chemicals had only been made up two days so should have been fresh enough. I considered light reversal, but hadn`t done so for some years and my one and only photoflood lamp had packed up, and besides I didn`t have any stop baths. Likewise this put payed to trying outdoors reversal. I decided to W&M a fresh 300ml of reversal bath and take a chance with that, and to my surprise this worked perfectly with neutral shadows! So what happened with the first reversal bath? I have made these baths up so often now that I feel sure that the weights and measures were spot on. The only difference in this instance was the `freshly` made up bath, I used exactly the same developers and bleach & fixer, and timings were the same, except allowing an extra 15 seconds for the second process.

JESSOP 3E6 KIT

For my next processing I used a Jessop`s 3 bath kit. This really simplifies the process, which the Jobo processor seems to have been design for. The shadows & rebates were completely neutral and without any hint of the tobacco effect, which appears to prove that the culprit is the CRC E6 formula for the reversal buth, but what this is I don`t know. But I was in touch with Rita pearle at the time and she sent me a copy of her `concentrate` reversal bath formula, which she says keeps for ages and works every time, so next time I try the CRC brew I shall give this a try. For those who would like to try it in the meantime here is the formulae:-

REVERSAL BATH

(Concentrated Dilute 1+9 for use). pH 5.75.

Water at 21 to 38 deg C -------------------------- 100.0 ml
Propionic Acid ------------------------------------ 60.0 ml
Stannous chloride --------------------------------- 8.3 gms
p-Aminophenol Solution * ------------------------ 2.7 ml
Sodium Hydroxide -------------------------------- 24.5 gms
B.D.H. No.4 -------------------------------------- 75.0 ml
Water to ------------------------------------------ 250 mls

* p-Aminophenol Solution (This will not keep)

p-Aminophenol ---------------------------------- 0.1 gm
Propionic Acid ---------------------------------- 1.0 m
Water to ---------------------------------------- 100 ml

This time I also tried processing two films back-to-back on the same spiral. The Jobo spirals are very thin and I had difficulty loading the films in. While on the main the films processed perfectly I lost 3 frames on each film where they didn`t receive processing. However, it proved this method will work and once I get the loading sorted out it will be worth doing. The Jobo is very economical on chemicals which would mean getting 8 x 36 exp. films processed from a 300ml brew. Altogether I am very satisfied with the CPE 2 plus which has proved such a bargain.