IRON + E.D.T.A - TROUBLE! says GLYN!
Glyn Willicombe again brings up the point regarding E.D.T.A. (Chelating Agent) plus iron in the water introducing a bleaching agent into the colour developer - which I mentioned in my Round -A- Bout column, in the January issue. Glyn now understands this is not the case.
But, says he, E.D.T.A. DOES accelerate the oxidation of developing agents when iron IS present in the mixing water, hence he has experienced inconsistent results - excellent slides from the fresh mix, poor colour, or even complete disaster thereafter, despite being well within stated capacity/usage/shelf life.
This is confirmation that the offending iron reacts unfavourably with the E.D.T.A. and he has now changed from using the EDTA FeNa4 bleach and reverted to the Ferricyanide type and this appears to have solved the problem. For iron in the water also reacts with the EDTA bleach giving a lack of aeration which is the reason for his returning to the `old` ferricyanide type bleach.
I should mention, as indeed Glyn does,that the current version of the C.R.C. formulae has been superceded by Chelating agent No. 4 ... and that members using this appear to have few problems.
But it is good to know, Glyn, that you didn`t just lie down and accept the inferior slides as `just one of those things`. No fear! A problem arises and has to be confronted... and solved.
Certainly a slide from Glyn,in the Area 20 Folio, and shot on Konica film and processed in the Arnold Moorhouse formulae, is a real beauty - and really does hold it`s own with the best.
In the booklet, circulating with the same folio, Oliver Barron reminds us that the water problem can be resolved by using distilled water. And that Oliver himself usually resorts to the thawed out frost or ice from a de-frosted freezer or fridge. I too have used this substitute for distilled water and found it quite satisfactory.
Ron Knowles (Area 11).
My thanks to Ron for the mention of copy being desperately needed for your Newsletter. We discussed this at the AGM and I am sure many of you now realise how difficult this situation is becoming, so please help back us up by considering something to write about. If you don`t the Newsletter is in danger of drying up and as this is the `backbone` that keeps the Club together, then the Club too could be in danger... We really do need to hear from you. Editor.