LETTERS TO THE EDITOR
Reg Cornish (Area 20):- It was sad to hear of Oliver`s death, that is indeed the end of an era. It reminds me of the monthly meetings at Uxbridge County Library - but then, travel was much cheaper (and Easier).
I think we have to face the fact that nowadays very few amateurs do their own processing. There are many reasons for this but the complexity of the process (if 5 bath) is probably the main one. Also, of course, colour prints from negs. are so easy and fast (1 hour at Boots) while Camcorders seem to be a coming rival for silver-based colour.
So I think a drastic reappraisal is needed for the C.R.C., which is easier said than done!
I suppose we should consider diversification in some way to spread our net wider. For instance:
1) I think we could drop `Reversal` from our name to become the `Colour Club`. Then we could include neg/pos and electronics (in the future) systems.
2) Greater emphasis might be placed on the art-form aspects of colour, especially in the Newsletter. Our more experienced members could contribute articles on specialised techniques, e.g. use of polaroids (filters), photography of animals and children (separately!), close-up work, flowers. The great thing is to give plenty of practical tips. I know from past experience how hard it is to get anyone to write anything, but I fear some effort must be made. I could offer articles on colour copying of paintings or on photo-micrography.
3) I know transport is a real problem these days, especially if one has no car. However it might be possible to fix up a quarterly or even monthly meeting somewhere. The problem is where? I know Slough Library has meeting rooms, but there is a charge, so there would have to be a guaranteed attendance. Perhaps this could be discussed.
Regarding the 3-Bath process process I have used the Jessop VE6 kit with excellent results. I process 4 films in two batches of two using a Jobo rotary processor and the times given in the instructions. As you suggest, I increase the between-bath washes a bit to keep the solutions free from contamination.
Brian Murphy (Area 15):- Thank you for publishing my letter in the April Newsletter and also for the very detailed and extensive reply in your letter of the 6th. Feb. I am now very encouraged to carry on with the freezing experiment, which seems to have received an endorsement in the July issue. I shall keep you informed of my results.
I took your advice on contacting Eric Weatherill on uprating film and I shall also follow his advice for my winter photography.
The Rev`d Ronald Hatfull. C. Chem. M. Chem. A. F.R.S.C. F.R.S.H. L.R.P.S. (Area 9) The July issue, Page 8, contains a statement that prolonged exposure to the atmosphere will change Sodium carbonate into Sodium Bicarbonate and the baking affected carbonate will drive off the absorbed Hydrogen and purify the salt.
The reaction suggested does take place when concentrated solution of Sodium Carbonate, or moist crystals, is saturated with Carbon Dioxide. I would be interested to hear the evidence that this change takes place to any significant extent merely on exposure to the atmosphere. The Atmosphere contains only about 0.03% by volume of Carbon Dioxide! There is, of course, no Hydrogen in the atmosphere which would be absorbed in the reaction which I have described, one molecule reacts with one molecule of Carbon Dioxide and one molecule of water to give two molecules of Sodium Bicarbonate. Sodium Bicarbonate can be converted to Sodium Carbonate, with the loss of water and Carbon Dioxide but I would suggest that this requires quite a high temperature - `Ignition` rather than `baking`.
Sodium carbonate is regarded as a very stable substance, such that it is used as a Standard Substance in Analytical Chemistry.
Sodium Carbonate commonly exists in three forms -
(1) With 10 molecules of water of crystallisation. Commonly known as washing Soda., or Soda Crystals. (2) With 1 molecule of water crystallisation. (3) Anhydrous. This is the form usually supplied for photographic use.
If (1) is left exposed to the atmosphere it loses 9 molecules of water of crystallisation and the crystals crumble to a white powder of the monohydrate (2). If (3) is left exposed to the atmosphere it will absorb water and be converted into the monohydrate (2).
It would seem that the monohydrate would be the form of choice, but it is not readily available commercially. The anhydrous form will remain so if it is kept in an airtight container. The decahydrate is unsuitable for photographic use as the composition varies according to the extent of the conversion into monohydrate.
Rita & Major Pearle (Area 13):- In the July CRCN (page 8) under BROMIDES, it is stated that "Potassium and Sodium Bromide are used as strainers". This should surely have been "re-strainers", which gives the statement an entirely different meaning.
We would like to join in the thanks and congratulations to Ron and Susan for their Life Membership. They certainly work hard for the club and well deserve a life membership.