Pyrocat HD in tubes? : LUSENET : B&W Photo - Film & Processing : One Thread

I've been thinking about using a pyro-based developer, and have pretty much decided on trying the Pryocat-HD formula listed on In the article, it says that when doing rotational development, you should use at least 75mm of developer. I use homemade BTZS-like tubes, so I assume that 75-100ml per sheet of film will be required.

I've also been reading on Usenet people's experiences with using the standard Pyro formula (and Rollo versions), but have had to resort to a 2-stage development since the developer seems to exhaust itself rather quickly (not sure about the Rollo version).

Has anyone tried the Pyrocat-HD in tubes? Does is behave differently than the Pyrogallo formulation in that it doesn't exhaust as quickly?


-- Ken Miller (, October 18, 2001


You don't say what size film, but I'm assuming 4x5. I don't have any experience with rotary processors, but... At 15 cents per liter of working solution, Pyrocat-HD is the cheapest film developer you can buy or mix. So, if I were you, I would try it with 100 ml. I regularly develop whole rolls of 120 sheet film (about equivalent to one 8x10 sheet film) in 500 ml., so I think 100 to 125 ml. would be about right for a 4x5. By the way, Pyrocat-HD is based on pyrocatechin, not pyrogallol, but both give good staining action.

-- Ed Buffaloe (, October 19, 2001.

Catechol or pyrocatechin developers (example: Pyrocat-HD) oxidize much like pyrogallol developers (example: PMK). When processed in trays or tanks with intermittent agitation, the oxidation occurs at a relatively controlled rate, which contributes both to the stain and the lovely tonality. With continuous agitation (rotary), both type developers oxidize too rapidly and underdevelopment will result.

I know of two ways to deal with this. One, and by far the simplest, is to increase the amount of developing agent (typically part "A"). I would try somewhere between 50-100% increase. With the activating agents used in most catechol or pyrogallol--sodium metaborate in PMK and sodium or potassium carbonate in catechol types--it will probably not be necessary to increase the activator.

The other alternative is to an additive to reduce the oxidation. I'm having a brain lapse at the moment and can't think of the chemical's name, but the trade name is Calgon. Also, I'd have to check my notes- -which are not with me at the moment--to tell you the amount to add, but if someone else cannot provide this, email me and I'll give you a starting point. I believe Gordon Hutchings mentions it in his Pyro book.

As I recall, the rollo pyro formula uses *both* these fixes.

Ahhh, it's call EDTA (Calgon)!

-- Ted Kaufman (, October 19, 2001.

Ed: Yup, 4x5. And I know that the HD formula uses pyrocatechin - I was comparing the stanard pyro formula with the HD formula. My only concern about using 100 ml is that the 'cups' of the tubes may not be able to hold 100ml without moving up into the threads, which would mean that I'd have to move very quickly when getting ready to develop.

Ted: EDTA is Calgon? Does this mean I can head out an buy some dishwasher detergent and use that? :-)

Thanks for the tips guys.

I may end up processing single sheets in trays just to be safe, but I may try the tubes anyways too see how it turns out.

-- Ken Miller (, October 19, 2001.

Yes, to the best of my knowledge, Calgon is EDTA. I'm not sure of the purity, but I think you can use it. You can always get it from Photographer's Formulary if you want the real thing.

You should not have any trouble using tubes to process your 4x5. Just increase the concentration of the developer. Nearly all pyro developers are quite dilute, so it's easy to double or even quadruple the developer (the actual developing agent)concentration and still work within your 100ml tube capacity.

I would recommend you begin by just doubling "A" as I said before (instead of, say, 10:10:1000, use 20:10:1000; if that's not enough, try 20:20:1000, or 30:15:1000, etc.). Test a sheet and see how it looks. If you really need to, add EDTA. But if you don't need it, don't complicate things.

-- Ted Kaufman (, October 19, 2001.

Thanks Ted.

I just put in an order for the HD chemicals sans EDTA from FotoChem in Quebec. I'll be picking up a scale tomorrow, so next should be interesting.

-- Ken Miller (, October 19, 2001.

I use Pyrocat HD both in trays and for rotary processing. Times are obviously different between the continuous agitation of rotary processors and the intermittent agitation of trays. I've experienced no trouble with rotary processing - I've read about the excessive oxidation and 'bombing out' with PMK, but I've never experienced this problem. I use about 300ml of working solution per 8x10 sheet (the usual 1:1:100, no increase in A solution etc). Maybe the problem turns up with the smaller amount of solution used in 4x5 film - the increased A solution should do the trick in that case. Good luck, DJ.

-- N Dhananjay (, October 21, 2001.

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