LATEST W&M TRIALS
By Bill Reid (Area 20).
As you may recall, last time I used commercial kits to process my holiday films as I had changed to Ron Croad`s modified version of the CRC E6 Formulae, and while having cured the `tobacco` effect, still hadn`t quite got the correct colour balance. Time and shift work is still very much against me and since that processing session in March, haven`t had the time to take enough film to have another go with the modified brew. However I slowly managed to get five cassettes of film exposed over the last six months and have had an interesting W&M and
processing session.I made up a 600ml kit and as far as I could make out, everything went very well. In fact! the pH values of all baths were within 0.5 of the official figures, leaving very little to do to bring them up/down to scratch, using 10% Pot. Hydroxide and, Acidic Acid. An interesting point was that the pH buffers I used to check my pH meter are the same as I made up back in 1990, (CRCN 56, page 13) from the pH pellets that Major Pearle kindly gave me during my weekend visit. These have certainly kept their power for a long time and were spot on at 25C. I don`t know how long they are supposed to last, but they are simply stored in well sealed 100ml glass bottles.
The only variation was in not using p-aminophenol in the reversal bath. Not by design, but simply that my supply of working solution had gone off and as Ron Knowles mentions, p-aminophenol is only used as a preservative and as I processed all my film the day after W&M, there seemed little point in messing about making up a fresh working solution.
During processing I also made two slight variations from official timings! It would seem that inspite of all the trials and many changes made to chemicals and suspecting my camera or re-loadable cassettes etc, the source of the `tobacco` problem seems to have been with the 2 minute timing in the REVERSAL bath! With no changes to the original CRC Formulae, for the reversal bath, I simply `doubled` the time for all films, in this bath, and over five films there is not a sign of the `tobacco` problem, in fact the films are perfectly reversed. It has taken a long time but at last, we seem to have cured this annoying problem.
The second change was in giving `5` minutes for the first wash after 1st. Developer, as it is suspected that if this isn`t sufficient, then there could besome reaction with the reversal bath that could cause the tobacco effect. Both these changes seem to have been worthwhile.
The only thing to spoil the processing is, that, as with my last trial with the modified formulae, I got rather `yellow` results. Hardly noticeable in many shots, but on others, very discernible. Some changes need to be done somewhere, but again, as I have little time for photography this could take a while to get back to. What I have been considering is that, with the original CRC Formulae, while I got the `tobacco` problem, the slides were otherwise excellent in overall colour balance, so what I intend doing is make up my next W&M to that formula and simply give the extended `first wash` and double the time in the reversal bath and see if this finally brings me back to the excellent results I got with my first W&M with the CRC Formula.
I have to admit that the long period of failures was bringing me to consider giving up W&M, but this latest processing makes me confidant that I shall eventually get back to the results I had reached earlier, before the `tobacco` effect set me back and, which members such as Ron Croad and others got right from the start, proving that the CRC Formulae is very good indeed.