Originally Posted by
esearing
Well documented in several Pyrocat HD problem threads. Photographers Formulary admitted they had some batches of Phenidone that were bad. They were also selling kits that were 3-5 years old in which phenidone will go bad before the catechin will. If you dilute HD too much for stand development, the catechol exhausts but there is not enough second developer to continue the processing. Pyrocat with Metol overcomes this problem because the Metol acts as the second developer and works extremely diluted. For example HD used at 3A+2B+500 will work great when developer is new for a single 4x5 sheet in a tank with minimal agitation. But after 6 months you will need to bump it up to 3.5+2.5+500 , after a year even 5+5+500 may be iffy. When negatives turn pinkish instead of the pyrocat brown, you have failure on the horizon.
My OA/2 (half stock strength) has been working for 16 months with no discernible failures that I can see. I divided the recipe by 10 but had a hard time getting it to mix at 100ml so I added water to make 200ml (half stock strength) and use 1.5:500 or 2:500 instead of 1:500 that the formula suggests. Pyrocat Metol lasted about a year before it turned blue.
For those that use diluted formulas remember that water quality will have an impact on shelf life and performance. But I would encourage anyone to make your own developers from scratch and experiment with it.
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