Capacity And Life Of Pyrocat HD

[thronobulax]

I am about to dip my (nitrile covered) toe into the Pycrocat HD but I am unable to find answers to the following questions. If some kind soul could help, it would be much appreciated:

• What is the working capacity of the mixed 1:1:100 and 2:2:100 working developers?
• What is the working life of these developers? If the developer is used less than the aforementioned capacity, can it be bottled in brown glass and subsequently reused?

 

[mpirie]

I'm sure others will chime in, but as far as I'm aware, Sandy King recommended 75ml of working solution per 5x4 sheet of film, so that's 300ml for 4 sheets or one 35mm 36exp or one 120 roll....in other words 300ml per 80sq in of film.

The life of the working solution is only an hour or so at most due to oxidation. With a 1+1+100 mix, you can afford to make up the working solution just before you need to use it. Don't mix it up and leave it for more than half an hour.

At the dilutions we use Pyro HD, it's not worth the risk of using a working solution once then keeping it for later use.....it'll have oxidised before you can use it with all the inherent risks that includes.

The concentrates last a long time. Part A goes off much quicker than Part B.

Mike

 

[thronobulax]

@mpirie More-or-less what I figured.

We'll see how this goes. The first roll of Agfapan - a throwaway 35mm of random subjects and lighting conditions - is washing right now..

I did the math and ordering premade solution from Formulary is not cost effective, so I ordered the bulk chemicals for future use. May as well put that fine analytical scale to work ...

 

[Alan9940]

Totally agree with everything Mike said. Definitely DO NOT use the solution over after a developing run; it would probably work, but the oxidation already present would lead to unnecessary and unhelpful overall stain. One point that seems to be of some question (for me anyway, at least) is the life of the concentrates. I've heard of folks having the solutions last for years when mixed in water, and even longer when mixed in glycol. I've been using Pyrocat-HD for many years and I've had it suddenly die on me twice! And, there was no indication that the developer wasn't working properly until I saw the negs following fix. That's a bummer! And, certainly disheartening. I will note here, too, that this happened with both pre-mixed product from the Photo Formulary and solution I mixed myself (and, I used to always mix Part A in glycol.) Nowadays, I mix small amounts in distilled water, store in brown glass bottles, toss it after about 6 months and mix new.

If you're planning to mix yourself, please make sure to use nitrile gloves, apron, and a face mask. Catechol is not something you want on you or in you! I always mix the catechol into the solution outside and I'm as careful as possible to avoid any dust from the chemical.

Good luck and enjoy this wonderful developer.

 

[thronobulax]

@Alan9940 Yes, I am long in the habit of using nitrile and eye protection when handling any of the Pyro variants. I'll also definitely wear an N95 when mixing the powders.

My first roll is done and the inspection was ... interesting. The stain is definitely A) different than PMK and B) Less pronounced than PMK. I was sort of expecting this. It's more of an overall brownish cast, which in my reading, appears to be "normal".

 

[Ian Grant]

You can't re-use it as the life once mixed is relatively short. The visible staining colour varies between films strongest I've seen is Fotepan 200 and HP5 but it's still staining even if less apparent with other films.

Yes economy of scal is important, I buy in larger sizes 25kg bags in some cases. Knowing wjat chemials cost PF prices seem rather a rip off.

Ian

 

[Alan9940]

The brownish stain is what you get with Pyrocat-HD; catechol stains yellow/brown(ish) and pyrogallol stains yellow/green. Not that you need to know that, but I thought you may find it an interesting tidbit.

In my experience, I have found that Pyrocat negs print easily on both VC and graded paper, while PMK negs print better on graded paper with VC results revealing lower contrast, especially in the high values. I think the yellow/green stain acts like your contrast filters in that it's removing some of the blue light. I used to use quite a bit of PMK back in the day of graded only papers, but since moving to VC papers in the mid-90's, then stumbling on to Pyrocat in the early 2000's I've not used PMK, again. Another aspect that I really enjoy with Pyrocat is its versatility in that I can do "regular" agitation, minimal agitation, and EMA (extreme minimal agitation) development and it works beautifully in each case. Oh, and I also run it in my Jobo using Expert drums.

Would love to see some pictures once you get it all sorted out. Have fun!

 

[thronobulax]

@Alan9940 Any experience with the 1:2:100 dilution model for higher developer activation?

 

[Ian Grant]

I totally agree with alan about how easy Pyrocat HD negatives print, to the extent taht it's now the only negative developer I use.

Normally I use Pyrocat HD at 1+1 to 100 in Jobo 2000 tanks for 5x4 these are the older (pre-Rotary) Inversion tanks, or Paterson tanks for 120/35mm. I've used 2+2 to 100 for tray developing 10x8 negatives essentailly to cut the development time, using at 1+2 to 100 will increase developer activity slightly probably needing roughly 20% time to achieve the same contrast as 1+1 to 100.

Ian

 

[Alan9940]

@Alan9940 Any experience with the 1:2:100 dilution model for higher developer activation?

No, sorry. I usually use 1:1:100 or 2:2:100 for denser negatives intended for pt/pd printing. The 1:2:100 dilution will definitely increase developer activity resulting in slightly shorter development times, but I've never really seen a reason for using this dilution.

 

[Alan Clark]

@Alan9940 Any experience with the 1:2:100 dilution model for higher developer activation?

Sandy King advised that a 1:2:200 dilution would give more edge sharpness when used semi-stand. I found that this worked well when I tried it, but gave no significant difference over 1:1:100.
The 2:2:100 dilution which you mentioned is one I have used a lot. It increases grain, which I used to like a lot in 35mm.

Alan