DK-50

[Julio1fer]

I have started cleaning my late father's chemistry shelves. He had about 50-year-old stuff which he had never touched since about 1980 or so.

There were a lot of dangerous chemicals to dispose of, but also some useful materials. Among them, two very old little yellow cans of Kodak DK-50 powder developer. Any comments or experience with DK-50 will be highly appreciated; I am inclined to try it just for the sake of it, after I finish my current Beutler.

FWIW, this is the Kodak formula for DK-50, from "Kodak Chemicals and Formulae", printed in England, February 1949 (3rd. Edition):

KODAK FORMULA DK-50 - Elon'-hydroquinone-'Kodalk' developer for normal-contrast negatives by dish or tank development

'Elon'. 2.5 g.
Sodium sulphite (cryst.) 60.0 g. (or anhydrous) (30.0 g)
Hydroquinone 2.5 g.
'Kodalk' 10.0 g.
Potassium bromide 0.5 g.
Water to make 1000 cc. Dissolve the chemicals in the order given.

By increasing or decreasing the quantity of ' Kodalk' in the formula it is possible (a) to increase or decrease the contrast obtained in a given time of development; (b) to decrease or increase the time of development without affecting the contrast.

Average development time about 10 minutes at 65° F. (18° C.) or as recommended for specific materials.


As we know, Elon is Metol, and Kodalk is sodium metaborate.

Compared to D-76. DK-50 has less hydroquinone and more alkali (in quantity and strength, Kodalk instead of borax). And less than half of the sulphite. So, it is probably more energetic than D-76, with not-so-fine grain.

The Massive Dev Chart features times for DK-50 - mostly quite brief. 5 minutes at dilution 1:1 for FP4+, for instance. Development is also short for faster films.

[LarryD]

Many years ago we used it in a large dip and dunk tank. It is not real fine grain. For home use I used to dilute it 1-2 and 1-3 because the times were so short. We used it mostly for 120 and 4x5 film. It was also a staple at the news paper when we needed to get something developed and printed to go to press in a hurry. I still have a can around here too. If you can hear it shake then 99% chance it is still good. Don't worry if you see some brown specks and crystals. It will be fine.

The larger grain is because of the higher alkalinity. If you want to play around with it you can use a little Borax in it ....