IN CONVERSATION (Part 2)

By Bill Reid.

One of the great pIeasures of being a Club `official` is being in touch with so many of the members, and on occasions meeting many personally. You can learn more from chatting than from many letters. I had the great pleasure of being invited to stay, over three days, with Rita & Major Pearle, at their home in Colchester, not to forget their son, John, who is so in tune with the family that on matters of photography they work as an excellent team.

The main reason for my visit, apart from the opportunity to meet everyone, was to try and sort out some of my processing problems. If you have followed my adventures you will recall that after some very successful processing earlier in the year, with the CRC Formula, this seemed to avoid me from then on and I suffered poor results with a `tobacco` effect. The slides appeared well processed as regards film speed, but the blacks were somewhere between `red` and a `tobacco` brown. This was inspite of W&M and processing exactly to my usual standards.

I took along, a fresh 300ml brew so that the pH values could be checked. This was carried out by John Pearle. The 1st Dev. was 9.9 (10), Col. dev. 10.9 (12). Reversal 5.3/4 (5.7), Bleach 5.91 (5.65) and Fixer 8.8 (6.6). As you can see by the correct values, shown in brackets, values were not too far out, with the fixer being the worst., none were so far out as to as to be the cause of the problem. John next brought the values up to the mark. To raise the 1st & Col. Developers, he added drops of Potassium Hydroxide (49% Sol.) and stirred in until the pH meter needle reached the desired mark. Sodium Hydroxide at 10% Sol. was added to raise the Reversal. (Proprionic Acid to lower). For the Fixer, again Sod. Hydroxide to raise, and Ammonia (25%) to lower. It wasn`t considered necessary to touch the Conditioner. It would appear that most times the pH values require raising rather than lowering.

I also brought 100ml of my previous Bleach and on checking this was found to read 5.8 (at 26,6C) which really wasn`t that far out.

The difference between `that` bleach and the latest brew was that I am now adding Potassium Nitrate to help the EDTA (NAFE) to dissolve, and some Ammonia, to re-balance the pH value. I noticed that Major`s bleach was very sludgy, though it didn`t stop the bleach working.

Still on the bleach, it is interesting that Major aerates the bleach, placing a plastic tube into the bottle, from a fish-tank ,air-pump. This of course is another debateable point, which Lawrence Edwards touches on in his latest article, in this Newsletter.

With all my chemicals checked out the next step was to try some processing. I was quite prepared to chance a full cassette of film (3M100), but Rita preferred to do a short test strip, using a colour test chart. This was a cassette of 3M100 film. With that done we processed the strip. I should add that I was using my usual `inversion agitation` so that results should be as if I was using my own set-up. Major uses `Rotational agitation`. The result, was a very `red` film base, no blacks what-so-ever!!! The first obvious suspect, of course, was my chemistry. Another test strip was exposed (from the same 3M100 cassette) and this was then processed in Major`s set-up. This consists of a large oblong flower trough. At one end two home-made plastic brackets fit onto the trough. In the centre `milled` notches of plastic, fitted to the tank lid and base, sideways, so that the tank is half submerged in the water. A fitting on the wall, above this, has an electric motor with a rubber wheel on the end of the spiral, so designed that when lowered, the rubber wheel turns the tank. The circuitry, controlled from a small box, reverses the motor every so many seconds, giving a very even and continuous agitation. It also allows one film to be processed in only 150ml of chemicals.

Water heating is from three immersed elaments giving over 400watts which very quickly heats up the trough, and is electrically controlled. A pump circulates the water for even temperatures.

In spite of this the second test strip, again resulted in a very `red` film, exactly as the first. As we had now used two different `brews` we came to the conclusion that the only common denominator was the `cassette` of film used for the test strip.

Another test strip was exposed, this time from a cassette of Agfa film, and given the same processing in Major`s set-up. This produced fully processed transparencies with excellent blacks.

With that Major decided to do some serious processing and loaded four films in his multi-tank. The films were, one 120, and three 35mm films, which included one of mine. Again these produced excellent results.

This successful,processing now left us wondering where my `brew` stood as regards `quality`!. So, yet another test strip was exposed (from the Agfa film) and processed in my chemicals, and again, using inversion agitation. The result was, as with Major`s brew, excellent blacks. The whites were a bit warm but Rita considered this was probably due to the exposure rather than the chemicals. But we had at last proved that my W&M was O.K. and it would seem, the first film used for tests must have been faulty in some way.

As we couldn`t work out what caused the `red` result, we decided to send the test strips, and the remaining unexposed film to our Secretary, Ron Croad, so that he could process it, and if he also got the same results, then it would be worth approaching the film makers for an explanation. As this cassette was the last of ten, and all others were perfect, it could either be a one-off or possibly it may have been affected when the supply came through the customs somewhere. I will keep you informed of any outcome.

To conclude on my very pleasant visit to Colchester, I had brought along a good number of sliders which were viewed over two evenings. I also enjoyed two short outings to some of their favourite photographic haunts. My grateful thanks to all for making my visit most welcome and enjoyable.

Initial suspicions for the `tobacco` effect was that of the pH values and might be cured simply by buying a pH meter and correcting the values. I had hoped this extra expense would not be necessary, but it now looked as if it had to be.

Tony Chuter very kindly offered to sell me his spare home-made meter, at a very reasonable price, though this would be doubled with the purchase of a probe and fittings, but it was a serious contender. However on my invitation to visit Rita and Major, they mentioned a `loan` of their digital C.P. pH meter. However, as it turned out, through their kindness this has been given to me as a sort of `permanant` loan, for which I thank them.

Simply purchasing (getting!) a pH meter isn`t the end of the problem, but in fact the beginning of yet more learning. The meter has to be calibrated by using pH `buffers`. The probe needs to be kept at around pH 7, which is `neutral` acidity, as for tap water. You next need buffers near to the pH values of each developing bath. Ron Knowles (Area 11) sent me some very useful information on the chemicals required to make up numerous pH buffers and which I produce here for your interest:-

Solution `A` 19.1gms of Borax, per litre of water. Solution `B` 13.6gms of Pot. di-hydrogen phosphate (An) per litre water. For pH 6 Use 12.3ml of `A` plus 87.7ml of `B`. For pH 7 Use 39.0ml of `A` plus 61.0ml of `B`. For pH 8 Use 55.0ml of `A` plus 45.0ml of `B`. For pH 9 Use 86.8ml of `A` plus 13.2ml of `B` For pH 11.72 Use 3.89gms of Tri-sodium phosphate per litre of water. For pH 9.18 Use 19.09gms of Borax per litre of water. Or pH 9.18 Use 1.99gms of Borax per 100ml of water. Please note that these pH values will be with the buffer solutions at 27C.

Thanks Ron, there is a great deal of useful information there for anyone starting to use pH correction.

While it was my intention to use the above list of buffer chemicals, John Pearle gave me a set of pH `powder` capsule, which if mixed with 100mls of Ionised/purified water, will give you a `set` pH value. The green capsule makes pH7, Blue capsule pH10 and the orange capsule pH4. These keep a long time and shows age by forming a fungus on top, when it is time to make a fresh lot batch.

To use for checking your pH meter, you first re-set your pH meter to pH 7 in the 7 buffer, at 25C, then when dipped into the other two buffers solutions, the meter should read 10 or 4, then you are ready to check the values of your developers. If checking, say the 1st Developer (at 27C), which should be pH10, dip the meter into the ten buffer (25C), then rinse in clean water, then with the developers at 27C dip the probe into the developer and in a few seconds it will settle at the pH value. If it is pH10, then fine. Rita and Major suggest that a difference of 1/10th could be ignored, but anything more will need to be altered by using small drops of the necessary chemicals that will raise or lower the values. Remembering that the `buffer` solutions should be at 25C and your developers at 27C, you can then check and correct all your chemical baths.

Frank White (Area 13) wrote saying that he had recently bought a new `expensive` pH meter. He had one of the C.P. digital ones, and it certainly worked, but he found that as it had no temperature compensation, in the recent hot summer the electronics were going "Haywire". Hmmm! I shall have to watch for that, should we get another summer like the last one!. Frank also mentions the need for some information on making up various pH buffers, so I hope he finds the enclosed information useful.

I got my supply of purified water from our local Boots. They had a large drum of it, but thankfully the resident chemist offered to sell me up to a litre. I had 500ml in a new bottle for $1.40. So there`s a tip, take your own bottle to your local Boots, and this will be even cheaper. I also bought six new glass, 100ml bottles. Three for the buffers and the others to replace the plastic ones In have some percentage solutions in as I suspect they may not be air tight enough for long shelf life.

Apart from suspecting my pH values for causing problems, I was also a bit worried about two of my chemicals - Pot. Thiocyanate (20% Sol.) and Pot. Iodide (0.1% Sol.). Frank White also touches on this and writes:- "I recently processed two more films, this time using my new pH meter. The results were a slight improvement, but they are like your`s, yellowish, tobacco-ish brown, but undoubtly not as good as they could be.

According to my references, Sodium or Potassium thiocyanate in the 1st. developer acts as an accelerator and effects the top blue sensitive layer. If there is insufficient, the top layer is insufficiently developed, there will be an increase in yellow i.e. a tendency to a yellow cast, and this is precisely what appears to be happening in the Konica film I and my friend, John Watt have both used, using the E6/7 published formula as originally published in the Oct. 87 Newsletter. Lawrence Edwards and the current CRC formula uses Potassium thiocyanate 20% Solution. Now Sodium thiocyanate anhydrous is available, but 1gm in the E6/7 does not equate to 1.04gms or 5.2ml in these later formulae. These chemicals can be interchanged, but not in equal amount, only in the rates of their molecular weights.

Bear in mind that this is anhydrous NA SCN in E7 (Oct. 87) so the 1gm of NASCN specified has to be replaced BY 1.2GMS OF KSCN.

1.0 X 97/81 = 1.19753GMS (1.2GMS)

Lawrence Edward`s Formula calls for 1.04gms of KSCN. Again calling for anhydrous. None of my catalogues lists Pot. thiocyanate as anhydrous but it is assumed it does not have any water of Katalisation. Thus the amount should be 1.2gms of KSCN, about 20% more.

The formula calls for 5.2mls of KSCN 20% solution, but as we have seen above, each gram of NASCN requires 1.2gms of KSCN".

Thanks Frank, I see what you mean and it is in with my worry over my supply of Pot. thiocyanate, which turned very `damp` and I wondered if this could give me a weak 20% solution. Major estimated that the thiocyanate could easily have absorbed up to 20% water. Therefore I have not only got a fresh supply, but it`s obvious that, unless you know your container is completely air-tight then you must make the dry chemical into a percentage solution immediately. Though in percentage, pot Iodide should keep indefinitely, having had my supply for some time now, I thought it prudent to make up a fresh lot, just to be sure.

Soon on my return from Colchester. I made up a compete fresh 300ml of developers, exept for the Bleach & Fixer which still has a lot of life left. With my set buffers at 25C and the developers at 27C I checked all the pH values. These were:-

As you can see, the two developers were just over 1/10th low. I use a plastic syringe (needle-less) to add the chemicals, and I found that, by adding 5-6 drops at a time, then stirring in, I raised/lowered the pH values a little until I got the correct values. It was very satisfying to know my next processing would be at the correct values.

And so, with all the developers completed and corrected, the next thing was to do the processing. I set up my equipment in the usual manner, with one change. I had fixed the tube from a fish-tank air pump into the bleach bottle, as Major has done. As Lawrence Edwards says in his article, this shouldn`t be necessary, but as it was working for Major I decided to give it a try. I should add that the air pressure is controlled by a screw-clamp on the tubing so that it just `bubbles` gently.

Another point, and which Lawrence Edwards clears up, is that of the `rinse` after Reversal & Conditioner. This was kept to, removing the spiral and giving the tank & lid a quick rinse, then giving the spiral a shake then replacing it back into the tank and immediately pouring in the Col. Dev. or Bleach. This would appear to be the best method to stick to. I have also omitted the rinse between Bleach & Fixer but while this works I don`t care much for the discolouring by carry over of the bleach, therefore I think the same `rinse` as described will help to extend the life of the fixer.

I had three films to process, one Konicachrome and two 3M Scotch Chrome. I`m pleased to report that this was very successful. In particular I was very impressed with the Konica, which is the first I have processed so far in the CRC formula. The blacks were very dense, with clean whites and very nice colour balance and little sign of the usual `blue` complaint of this film. Likewise, the 3M films were perfectly processed. So it seems I have come full circle and finish the year with the same excellent results I started off with.

Of course, one Swallow doesn`t make a Summer! therefore only by the repeating the success with a completely fresh brew would confirm my W&M a constant success. Having made up a fresh brew and carried out a pH check I processed three more films and had another very successful run. Again, one Konicachrome which also confirmed my earlier comments on how well this film processes in the CRC formula. The other two were quite old 3M 400asa films and while some deterioration was visible, the chemistry had done its job well.

In conclusion, I feel I can put the source of that `tobacco` effect down to my supply of Pot. thiocyanate solution and that most other things I suspected can be omitted. Obviously when you get problems you have to check every possibility. I think too, the CRC formula can be looked on as a very `able` brew and that all W&M`s should give it a try, especially if they aren`t having much success with their regular brews.

Tony Chuter (Area 17) is so enthusiastic about the CRC formula that he has prepared enough `test` slides to send one to all CRC members to prove what the formula can produce. Tony`s article arrived too late to be included in this Newsletter, but I have duplicated copies which you will receive along with this N/L as an `Additional`. We feel that you will be very impressed with this slide quality.

My thanks to everyone who has helped me to sort out my processing problems. It makes being a CRC member very rewarding. WE hope that many of you will now try the CRC formula. Please let us know how you get on. If you do find problems, which you shouldn`t after following my `ventures`, you will at least know there are plenty of fellow members only too keen to assist.

If you now wish to try the CRC formula you should have the full details in your Club Handbook. A `Starter` chemical list & prices are given on the front page CRCN No52. You should also have the latest chemical list in the Oct. issue No. 55.

If you write or phone Secretary, Ron Croad (Address & No. Page 2) he will be pleased to give you every assistance.

Don`t forget too, the very keen prices of our Club`s film sales.