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What is a "clean working" developer?

Michael the term clean working is used by many companies, Ilford, Kodak, Champion, Dupont etc and has been for many years to describe various developers, film and paper, one shot and replenished.

Crawley divides developers into different types, and one type is "physico-chemical developers" - which includes D76, D23, Nicrodol(-x), Perceptol, Microphen etc. These all use Sodium Sulphite as a silver halide solvent (Microdol & Perceptol use additional solvents as did DK20). None of these developers are as clean working as the Buffered, non-solvent or " chemical " developers; e.g. DK.50, D.61A.

However by careful formulation developers with a high sulphite level can be produced which are cleaner working than say D76, Adox Borax MQ and Xtol are two examples. A side effect of a cleaner working developer is it's less likely to sludge up with colloidal silver when replenished.

Ian
[h=2][/h]
 
I ran a few rolls of polypan through it using carbonate as alkali (metaborate being virtually unobtainable in the UK).
struggled a bit with it, development times were in the order of 3 or 4 mins, but the best negatives were extremely sharp and had marvellous highlight separation.
didn't pursue it but if I had more time and money and wanted to sacrifice film in experiments, I might have another go
 
No doubt you have the metaborate to hand, so I'll be interested in your results.

I did also substitute the correct proportions of borax and sodium hydroxide for the metaborate (as well as abortively trying to make metaborate using the Mike Wilde method), and got just as short development times. But my best results were with carbonate.
 

The higher pH 9.8 as opposed to the pH 8.5 of D76 is the treason for the short development times.

Ian
 
Ian I'm not sure how D76 comes into it?
 
ah gotcha
 
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