is pyrocat hd a one-off developer?

jvoller · Dec 28, 2014

I just tried Pyrocat HD for the first time yesterday (using the liquid version), and developed a single 4x5 neg. as a test; it came out perfectly. I then bottled the solution -- I'd mixed up 1000ml, using the standard 1:1:100 ratio in distilled water -- in a collapsible bottle, figuring I could develop a few more negs. with that batch. Today, when I poured the solution into my tank (I use a Patterson tank w/ MOD54 holder), I noticed the Pyrocat solution was dramatically darker than it was when I poured it into the collapsible bottle yesterday. But I went ahead and developed 2 more 4x5 negs, and both came out completely blank. I then used some of the same batch of developer on a roll of 120 film, and the same thing: completely blank. When I poured the developer out, it was even darker, an extremely dark brown and nearly opaque. Did I miss something about Pyrocat? Should be it used once - even just for a single neg -- and dumped? I'm a bit baffled by all this..

SchwinnParamount · Dec 28, 2014

Odd. I just developed 8 4x5 negatives in Pyrocat HD that was nearly black when mixed. The A and B solutions were at least 2 years old in their respective bottles but mixed together immediately before I developed the film. The negatives came out fine.

JW PHOTO · Dec 28, 2014

Once A is mixed with B life is short. Almost all Pyro developers are that way. John W

TheFlyingCamera · Dec 28, 2014

As previously mentioned, pyro developers are one-shot, mix-and-use developers. Do NOT try to re-use pyro of any flavor, and don't mix to working strength more than about a half an hour before use.

jvoller · Dec 28, 2014

Thanks to all who replied. I hadn't seen references to Pyrocat being a one-off developer, but now I know. And know where to ask before taking the leap next time....

Rick A · Dec 29, 2014

Probably every question you have about Pyrocat-HD answered here.

http://pyrocat-hd.com/

jvoller · Dec 29, 2014

Rick A said:
Probably every question you have about Pyrocat-HD answered here.

http://pyrocat-hd.com/

I had come across this page, actually, and one of the links there to a page about "pyrocat preservation" is what got me into trouble. That page contains the statement "Pyrocat developers already have a long shelf-life" so I figured I'd be OK to re-use a batch of pyrocat-hd less than 24 hours after I mixed it. I'm now assuming that 'long shelf life' refers to the components of pyrocat developers *before* they're mixed.

I knew I should have paid more attention in chemistry class...

Sirius Glass · Dec 29, 2014

jvoller welcome to APUG

TheFlyingCamera · Dec 29, 2014

jvoller said:
I had come across this page, actually, and one of the links there to a page about "pyrocat preservation" is what got me into trouble. That page contains the statement "Pyrocat developers already have a long shelf-life" so I figured I'd be OK to re-use a batch of pyrocat-hd less than 24 hours after I mixed it. I'm now assuming that 'long shelf life' refers to the components of pyrocat developers *before* they're mixed.

I knew I should have paid more attention in chemistry class...

Yeah - the stock solutions separated into their A & B parts will last at least a year, longer if you get part A in glycol instead of water. Do pay attention when they start getting old, though, once the bottles are more than half used. Pyrocat (and other pyro developers, to the best of my knowledge) have a nasty habit once they get near the bottom of the bottle to start oxidizing rapidly and you'll have one batch that will be A-OK, and the next batch will have significant development failure (I've ruined too many sheets of film this way... it was most noticeable when working from an aqueous solution, thus my switch to a glycol-based version). If you go through it fast enough, this won't be a problem.

john_s · Dec 29, 2014

Rick A said:
Probably every question you have about Pyrocat-HD answered here.

http://pyrocat-hd.com/

A useful site, but be aware that there is a mistake in the instructions for mixing Pyrocat-MC. The sentence "Pyrocat-MC can be mixed without the TEA by starting with the glycol at about 150º F, and stirring each chemical into solution." is corrected later under the heading "Alternative mixing directions."

See also the thread at:

(there was a url link here which no longer exists)

for Sandy's correction.

Tony-S · Dec 29, 2014

jvoller said:
Thanks to all who replied. I hadn't seen references to Pyrocat being a one-off developer, but now I know. And know where to ask before taking the leap next time....

You should give 510 Pyro a try sometime.

Gerald C Koch · Dec 30, 2014

Diluting the stock solutions 1:1:100 was a clue that this was a single use developer.

Bob Carnie · Dec 30, 2014

What John said.. very short life , I would never consider reusing.
Chalk this one up to experience

jvoller · Dec 31, 2014

Definitely an 'experience,' but the end result is quite promising. I've developed some more negs in Pyrocat HD in the past couple of days, as well as comparison negs in two other developers, and find the Pyrcat-developed negs much more to my liking in terms of grain, acutance, and highlight texture. Time to order more Pyrocat.

Thanks again for all the responses.

SchwinnParamount · Dec 31, 2014

Now I'm worried about my next effort in the darkroom. As I said on page 1, I used 2 year old + Pyrocat HD from Photographers Formulary. My A and B bottles were nearly full when I got them from PF, but now I've used about 2ml out of each. In the last few days, A and B have been stewing in their individual bottles with a little bit more air. Should I make one more working batch for tonight or go to my newest fav, Obsidian Aqua?

Gerald C Koch · Dec 31, 2014

Probably best to transfer part A to several smaller bottles.

Ian Grant · Dec 31, 2014

Actually there are Pyro developers that can be replenished but they have a high Sulphite level and no staining takes place. HC110 used Pyrocatechin at one tme and that could be replenished.

Ilford sold a Deep tank developer with a small quantity of Pyrogallol alongside Metol & Hydroquinone and a replinisher, very clean working the Pyro acted as an oxygen scavenger.

My experience is that stored in glass or high density plastic bottle Pyrocat HD Part A made up in distilled or deionised water will last over 3 years as long as the Pyrocatechin and particularly the Sodium Metabisulphite are reasonably fresh. Once the Metabisulphite has decomposed to sulphite Part A collapses quickly.

If Part A has started to change to a darker colour it shouldn't be used as you run the risk of uneven staining of the gelatin of the film base.

Ian

Michael Wesik · Jan 2, 2015

Ian Grant said:
Actually there are Pyro developers that can be replenished but they have a high Sulphite level and no staining takes place. HC110 used Pyrocatechin at one tme and that could be replenished.

Ilford sold a Deep tank developer with a small quantity of Pyrogallol alongside Metol & Hydroquinone and a replinisher, very clean working the Pyro acted as an oxygen scavenger.

My experience is that stored in glass or high density plastic bottle Pyrocat HD Part A made up in distilled or deionised water will last over 3 years as long as the Pyrocatechin and particularly the Sodium Metabisulphite are reasonably fresh. Once the Metabisulphite has decomposed to sulphite Part A collapses quickly.

If Part A has started to change to a darker colour it shouldn't be used as you run the risk of uneven staining of the gelatin of the film base.

Ian

I would only add that if the bottles are not completely full, the deterioration of Part A happens much more rapidly. Rather than using 1L bottles, I use several smaller bottles to split up a batch.

is pyrocat hd a one-off developer?

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