Michael Taylor wrote:
> From: Michael Taylor
> To: The AltGroup
>
> Compare and contrast the following 2 statements.
> 'The benefits of this [PMK dev] I have found to be greatly overstated. In particular, its variable colour of stain with differing emulsions gives variable results with VC paper. The yellow-green stain which is most marked on HP5Plus, FP4 and TRI-X, gives distorted and often unpleasant tones on these papers, though occasionally it can be made to work. It does work well on graded papers though.'
>
> Barry Thornton, The A-Z of Ilford Delta 100, Professional Photographer, March 1996
>
> Barry then lists the following formula as providing superior sharpness, better and stronger staining and non-actinic brown stain (neutral effect on VC papers) compared with PMK..
> It is also very economical and long-lasting.
> The formula is:
>
> Bath A conc.
> Pyrocatechin ...................... 10 g.
> Sodium sulphite ..........2 g.
> Potassium bromide ....0.5 g.
> Water to 100ml.
>
> Bath B conc.
> Potassium hydroxide ....10 g.
> Potassium bromide ......0.5 g.
> Water to make 100ml.
>
> Development Sequence
> Both are mixed at 1+14 to make separate A and B working solutions.
> Time for nearly all films is 4 minutes in each bath at 21 C.
> Agitation is once every 30 secs in bath A, once every minute in bath B.
> No rinse between baths.
> Normal stop and fix after.
> (NB: No post fix bathing in alkaline solutions required by PMK.)
>
> Although not intended for Jobo rotational development, I'd be interested to know if anyone has tried this (or a similar formula) with the Jobo system.
>
> Also, it is only a starting point for further refinement.
>
> Note: Rodinal 1+25 is a compensation type developer so theoretically is not for Jobo use but I get great results with it for almost any film in my Jobo system!!
>
> PMK Pyro: UK Supplier
> Note for those who have difficulty obtaining chemistry (or time!) to make their own PMK dev. there is a UK source for PMK Pryo:
>
> Photo Chemical Solutions,
> 7 Stand Rise
> Radcliffe
> Manchester
> M26 1BT
>
> TEL: +44 [0] 161 280 2406
>
> Also check out the usual Bostick & Sullivan (USA) and SilverPrint (UK). Both have web sites of the same name!
> (NB: I do not have shares in these business! - they were helpful in the past...)
>
> THANKS
> Many thanks to the group for the advice about:
> pre-bathing in sodium metaborate
> using the A and B PMK baths separately
> not using Photoflow (which I never use anyway!)
> using EDTA
> using the Jobo Expert 3005 drum rather than the 2500 series (damn fiddly in the dark!!)
> etc..
>
> My Questions About PMK Pyro In the Jobo ATL-2 system
> 1 Due to Pyro staining is it better to keep a set of spirals/tank separate from all other processes eg, Rodinal, E-6, C-41 etc...?
> 2 Which rotation speed is best for Pyro?
> 3 Is the agitation method on the ATL-2 of bi-directional rotation plus up and down movement better than simple rotation ?
> 4 Can wash cycles at 20 C in a plumbed-in system be used at any stage ?
> 5 How do you get the spent A+B alkali Pyro mix back into the sequence (or is this a silly question!) ?
> 6 Is it better to use the higher temperature (and thus shorter times to minimise aerial oxidation ?
> (NB: Oxygen could also be excluded by filling the drum almost completely full of the A+B mix but for a 3005 drum could be an expensive way of eliminating air!!)
> 7. Should the ISO be halved for Pyro developer (eg HP5+ at 200ISO; FP4+ at 50 ISO) ?
>
> Yet Another PMK Reference
> See Norman Wilson (I had to get another Irishman in somewhere!) in
> 'Pyro Technics', Darkroom User, Spring 1995
> (100410-1561@compuserve.co.uk)
>
> Yet Another A/B Formula!
> For any T-Max 100 (TMY) sceptics the following formula given by Joe Englander in Ag+, Vol.9 (now published by BJP) might be worth a try:
>
> A
> Water (52 C)................ 750 ml.
> Metol .......................... 10 g.
> Sodium sulphite .............75 g.
> Cold water to make ...........1 L.
>
> B
> Water (20 C) ................750 ml.
> Sodium sulphite ................5 g.
> Sodium carbonate ............15 g.
> Water to make ..................1 L.
>
> DEV SEQUENCE:
> 3 mins dev in part A
> no rinse
> 3 mins in part B
> (Jobo @ 50 rpm with same times)
> water rinse
> fresh fixer
> wash normally
>
> The initial ISO is a true 100 ISO.
> Results: overall contrast is normal (NOT flat as with many A/B systems) yet mid range contrast gives good separation. Highlights are smooth/full range. Good A/B-style shadows. Could be useful for alt Proc.
>
> Hopefully this is helpful to someone and I have not been too long-winded an Irishman !...
> God Bless
>
> Michael.