Need Help Understanding Working Solutions of Pyrocat HD

Hi, I have been reading everything I can find on Pyrocat HD. In regards to the working solution ratios, there just seems to be advice on which ratios to use and no underlying information on "why" the working solution is suggested.

I am trying to better understand the role of solution A and Solution B independently, and then how they relate to each other for the various working solutions.

Does anyone have knowledge or know of a resource that actually explains the role of each solution and their effects on development when used in various ratios? I have read everything I can on Sandy King's website, and followed all the links on pyrocat-hd.com and I am not finding the information I am seeking.

In other words, why is a 1:1:100 suggested for silver gelatin papers and what happens if I were to change the ratio of A to B (e.g,. 1:2) or B to A (2:2) or the overall dilution from 100 to 200 or whatever. By understanding the role of each solution and the effects of dilution, I can have the info I need to make an informed decision. There is no point in me performing tests if I don't understand the variables.

For example, here is the type of information that is available:

For developing negatives intended for printing with silver gelatin papers the recommended working solution is a 1:1:100 dilution.One Part Stock Solution A + One Part Sock Solution B + 100 parts water.

For printing with AZO and most alternative processes, including carbon, kallitype, Pt/Pd, Vandyke, POP, albumen, and salted paper, a 2:2:100 solution is recommended. Two Parts Stock Solution A + Two Parts Stock Solution B + 100 Parts water.

In a nutshell, alternative processes usually need a thicker, contrastier negative since they have a greater scale than silver prints. That is why the stronger dilution is recommended. The stronger dilution helps prevent loss of activity due to oxidation as well and may be suitable if you are using a JOBO depending on your preferences. If you are silver printing then the 1:1:100 is usually the way to go. The only way to know how you want to use it yourself is to use it and adjust if you don't like the results. I experimented with different dilutions over the years, but I just use the standard 1:1:100 these days with my preferred Pyrocat-PC. I have found it produces enough density to achieve the thicker than normal negs that I prefer. Keep in mind Pyrocat negs tend to look thinner than they print due to the stain.

Hope that helps you.

Hi Patrick, thanks for the info, it helps me piece things together.

I am also trying to understand the impact of the dilution 100, 200, 400, etc. For example, you use 1:1:100 for silver printing. What happens to the negative when you try 1:1:200 for example?

Patrick Robert James said:

In a nutshell, alternative processes usually need a thicker, contrastier negative since they have a greater scale than silver prints. That is why the stronger dilution is recommended. The stronger dilution helps prevent loss of activity due to oxidation as well and may be suitable if you are using a JOBO depending on your preferences. If you are silver printing then the 1:1:100 is usually the way to go. The only way to know how you want to use it yourself is to use it and adjust if you don't like the results. I experimented with different dilutions over the years, but I just use the standard 1:1:100 these days with my preferred Pyrocat-PC. I have found it produces enough density to achieve the thicker than normal negs that I prefer. Keep in mind Pyrocat negs tend to look thinner than they print due to the stain.

Hope that helps you.

Click to expand...

The 1:1:100 is the "standard" dilution typically used to produce negs for silver printing, as you've already learned. The 2:2:100 dilution is a more active mix suitable for obtaining contrast in the neg for alt process printing. Many folks up the water ratio to, say, 1:1:300 to make a softer working mix for developing x-ray film. Basically, it all boils down to experimentation, if you're so inclined. However, I'd highly recommend picking one of the standard ratios to start; depending, of course, on your intended print medium.

Hi Alan, thanks for the reply. I guess that is my point... I am trying to understand the variables so that when I change one of them in my testing, I understand the intended impact of that change. What I have gathered so far is that the higher ratio of A+B produces higher contrast negatives, often desirable for alternative printing. The development method (e.g, stand, semi-stand, trays, Jobo, etc.) will impact the contrast of the negatives too. I assume by upping the overall dilution from 100 to 200, 300 or beyond, would decrease the contrast because there is less active developer in the working solution.

Alan9940 said:

The 1:1:100 is the "standard" dilution typically used to produce negs for silver printing, as you've already learned. The 2:2:100 dilution is a more active mix suitable for obtaining contrast in the neg for alt process printing. Many folks up the water ratio to, say, 1:1:300 to make a softer working mix for developing x-ray film. Basically, it all boils down to experimentation, if you're so inclined. However, I'd highly recommend picking one of the standard ratios to start; depending, of course, on your intended print medium.

Click to expand...

the thinner the mix, the longer the development and the less agitation the more edge effect.
dont expect miracles. and yes, if you want to see what you can achieve, you will have to try it out.
shoot x rolls of the same, or cut one roll into x parts and try every combination you want.
its the only way that will tell you something of importance. and then print to see how you like it.
every workflow is different, experimentation is key.
just my opinion..
chris

Since I don't see it mentioned above: Solution A contains the developing agents (pyrocatechol and phenidone/Metol) and the restrainer (pot. bromide), solution B contains the alkaline accelerator (sodium carbonate). Too little solution A for the amount of film your developing will exhaust all the developing agents before the developing is complete and you'll have underdeveloped negs, so be careful with high dilutions. Same with the carbonate: less of it means less developer activity and slower developing; more and it will speed things up. I'll often use more accelerator in the mix when I'm doing expansions (N+).

Finding an optimum dilution for a developer takes lots of testing, and that is usually done by the person/company/lab that created the developer, hence the aforementioned recommendations. Feel free to experiment, but be aware that you may be moving away from optimum if you do.

Best,

Doremus

Doremus, this is exactly what I was looking for! Thanks for your help.

Doremus Scudder said:

Since I don't see it mentioned above: Solution A contains the developing agents (pyrocatechol and phenidone/Metol) and the restrainer (pot. bromide), solution B contains the alkaline accelerator (sodium carbonate). Too little solution A for the amount of film your developing will exhaust all the developing agents before the developing is complete and you'll have underdeveloped negs, so be careful with high dilutions. Same with the carbonate: less of it means less developer activity and slower developing; more and it will speed things up. I'll often use more accelerator in the mix when I'm doing expansions (N+).

Finding an optimum dilution for a developer takes lots of testing, and that is usually done by the person/company/lab that created the developer, hence the aforementioned recommendations. Feel free to experiment, but be aware that you may be moving away from optimum if you do.

Best,

Doremus

Click to expand...

dear analog 55, my recommendation to you .... is to experiment, try all the dilutions you want,a.k.a. "test your film" find the one that best suites your needs, find the dilution, the time, the aggitation method, that gives you the best results for your intended vision. IMO that is why Pyro cat HD is great, 1. its sharpness, its ability to work for alt. process. its ability to work for silver paper. it has latitude and it is cheap. all the better . make sure you take good notes on all your tests, be methodical, and above all have fun

Thanks Greg. I agree. My goal was to understand the variables so that I had some sense of what I could modify when making negatives for my style of photography. Thanks to everyone here, I have a much better understanding of each variable and now I can move forward and make adjustments until I find what works best for me. APUG is awesome!

greg zinselmeier said:

dear analog 55, my recommendation to you .... is to experiment, try all the dilutions you want,a.k.a. "test your film" find the one that best suites your needs, find the dilution, the time, the aggitation method, that gives you the best results for your intended vision. IMO that is why Pyro cat HD is great, 1. its sharpness, its ability to work for alt. process. its ability to work for silver paper. it has latitude and it is cheap. all the better . make sure you take good notes on all your tests, be methodical, and above all have fun

Click to expand...