PERCENTAGE SOLUTIONS
AREA 20 Newsletters.
In Olver's latest N/L's there has been notes on making up percentage (%) solutions and their keeping qualities. Our Chairman, Bert Sanders had written to him suggesting an article on using & solutions for the Arnold Moorhouse formulae, as it is less trouble than weighing to measure a few ml of various solutions. Oliver gave this some thought but although there have been a number of all-liquid kits on the market, he hesitated to put his own ideas on paper as one can so easily mix chemicals, both in isolation or combination and find that after a while, interaction, oxidation, and or other unwanted chemical effects have resulted in unsatisfactory processing.
Never make solutions of developer agents .. mono or colour .. to keep. They oxidise rapidly. Sodium Hydroxide has a poor life in solution. It
obsorbs carbon dioxide from the air and forms sodium carbonate. (Up to six months in a well-stoppered bottle should be alright Sodium sulphite changes to the sulphate in solution. Oliver used to keep a 20% solution and never had any trouble but only kept it for a few months.
Referring to Oliver's chemical list, the following items should be alright as solutions, virtually indefinitely:-
Items No's 8, 14-20, 22-25, 27, 28, 31, 32, 37. Items 26 and 30 as above. (Update 200. These refer to Olivers chemical sales list, numbers)
However, there are chemicals in the A.M. formula which will keep a log time ... certainly a year and probably longer ... in solution and I suggest thefollowing procedures:-
First of all, prepare 20% solutions (20gms in 100ml of water) of calgon, Pot. thioccyanate, Pot. Bromide, Sodium Hydroxide, Sodium Sulphite Anhyd.and triSodium phosphate Cty. Also mix some 1% Benzotriazole, and 0.1% Pot. Iodide. (1% is 1gm in 100ml of water and 0.1% is 100gm in 100ml of water).
I suggest you make up enough for 10 litres of each developer. The quantities required will be in the above order:-
If Oliver's arithmatic is correct the following formulae will give the same brew as given by Ron Croad in his article in CRC News No. 38, July 1985.
| Now make stock solution X as
follows:- Calgon
20% sol.
100ml Calgon 20% Sol.
100ml Working D1. S. Sulphite
20% sol.
180ml
Working D2. S. Sulphite
20% sol.
20ml |
Use undiluted, in D1 Use undiluted, in D2 Do not keep longer than 1 year
|
It may seem that there is little to be gained by this procedure but you can make up the various % solutions at your leasure. Likewise, solutions X & Y can be quickly mixed from the % solutions. At the time of processing you have only to weigh Hq & Phen. for D1 and CDA & CD3 for D2.
* Borax can be kept as a percentage solution, hoever it is not very easily dissolved in water, even when hot, so mix a 5% sol. and use 160ml in a litre of developer, equivalent to the 8gm quoted in the formua.
Concentrated or working solution of Pot. Ferri. bleach and Hypo Fix keep indefinitely or until exhausted, as evidenced by taking an exessively long time to operate. An incomplete bleaching or fixed film can be saved by washing and rebleaching and fixing in fresh solutions.