MORE PROBLEMS MATE!

By Bill Reid

Those (still) following my excursions into weighing & mixing will remember that last time I had suffered problems of very dense slides and having to extend the first development time to ten minutes to gain normal film speed.

To cut a long story short, this problem would appear to have been due to my camera having a progressive shutter fault. This came to a head (When else?) while on holiday last July. Just half way into my second cassette the shutter refused to fire. As luck had it I had a Marinda Compact camera with me and was able to use that for the remainder of my holiday.

This proved some points during the processing which was done using a Barfen 6 film kit. I first processed the films taken with the Miranda Compact and these processed perfectly to full film speed using normal timings. I then processed the two cassettes from my faulty Canon AE-1, remembering that last time I had to give 10 minutes first development. So allowing for the previous films I gave 10 1/2 mns in the first developer and got perfect results. It would seem that leading up to the complete failure, my Canon had been firing for one speed only, causing underexposure, hence my puzzlement in having to give such long development times.

I have since had my camera repaired by Morris Photographic Centre, High Street, Oxford. I received an estimate within the week and the camera was ready for delivery in just 2 1/2 weeks altogether which I thought was excellent service and would highly recommend anyone to use this dealer. The camera required a new shutter solanoid.

As winter set in it was some while before I could give my camera a really good trial. However during late Summer I had made good use of the Miranda Compact and eventually had enough film exposed to try some weighing & mixing.

At this time I had bee introduced to the Modified formula which makes up concentrate developers and was keen to give this a go. I took every care to get the weighing & mixing right, centering the chemical holders for each chemical, so I was sure all had gone well. But sad to say I got the most terrible `blue` results and somewhat contrasty. While I had got dense results with the normal A.M. brew, colour balance was quite good, so I decided to make up a fresh 300ml of this colour developer and try again. The results were much nearer the mark. pH had obviously been wrong with the concentrate formula!.

I got onto Ron Croad and after some debate he thought the problem may have been due to my having used a couple of alternative chemicals, i.e. Potassium instead of Sodium or vice versa. So Ron kindly sent me the correct chemicals involved and I planned another attempt. Note that these two A.M. formulae does not use alternative Pot. or Sodium chemicals, which as far as I know, isn`t explained.

Once again I took great care in weighing & mixing and felt all had gone well. Also by this time I had made the trials with the Maplin Electronic Thermometer which I reported in the April Newsletter and to add to this I was able to do a bit more fine tuning and now have the UNO Thermostat Heater holding the bottle temperature between 38.04C to 38.01C, so the Maplin thermometer has proved a worthwhile purchase. I also had a few Konica films (Club sales) exposed with my repaired camera.

However in spite of all this care and effort I got exactly the same `Blue` results as previously and was very disappointed, and somewhat puzzled, as indeed was Ron Croad. As I had so many failures I decided to halt further processing with this formula until the problem was solved.

It is an interesting point that the only difference from the normal A.M. formula is that these were made up as concentrate developers and I wonder if this is where the problem lay. A week or so later while reading some technical matter, it mentioned that in using a seperate CD3 in concentrate form, Potassium Metabisulphate was added as a preservative and as this is a very strong alkali powder it drops the pH quite a bit and compensation will be required.

After further discussion Ron agreed that this could well be the source of trouble with this formula, but he cant understand why he doesn`t get this problem while using this formula. Likewise it would seem obvious that this would have been taken into consideration in the early stages of producing the formulae.

So for the moment this is where things stand. When I first made up a brew from weighing & mixing I had no access to a pH meter, but when getting this checked by Tony Chuter the pH value was spot on and while I got those dense results the colour balance was very good. It would appear that for the concentrate developers a pH meter is necessary to assure correct values.

I haven't given up on further weighing & mixing but after so many losses I would like to get some useful slides and will process the remaining films with a commercial kit. I think too there is little need for a concentrate brew if you are going to process all your films within a week or two of making up the developers. Therefore I intend to stick to the normal A.M. formula for my future weighing & mixing trials. In the meantime if anyone has any further ideas on this I would be pleased to hear from them.  

OPEN MEETING (Footnotes)

Re- Dr, G. Niell:- I have received a letter from Dr. Niell. He explains that after getting home he checked his AV equipment out and found everything in perfect order. During his programme he asked if we got problems of voltage fluctuations in the area. During the remainder of the slide programmes I kept a check on the proceedings and all went very smoothly. However there are a number of wall sockets around the room used and it may just be possible that the one that Dr. Niell had chosen may have been faulty in some way. I`m sure you will all be pleased to know to know Dr. Niell's projectors and recorder are in good order. If it was a case of a faulty socket my apologies are in order. I will have the sockets checked for our future meetings. Ed.