Pyrocat-HD Process times for other dilutions

[Alan9940]

Normally, I use Pyrocat-HD at 1:1:100. Is there some factor that can be applied to your development time for other dilutions such as 1:2:100 or 2:2:100?

Thanks

 

[Andrew O'Neill]

I'm not aware of a factor... I do however sometimes use 2+2+100 for HP5, and couple other films.

 

[Alan9940]

I'm not aware of a factor... I do however sometimes use 2+2+100 for HP5, and couple other films.

Yeah, I've used 2:2:100 for HP5 for pt/pd printing. But, what I'd like to do here is: let's say the MDC indicates a developing time of 18 mins for Pyrocat-HD at 1:1:100; any stronger dilution will require less time, right? I'm also using minimal agitation, but I'm pretty sure I have that figured out. I really don't want to waste 8x10 film testing, but it may be the only way to derive the answer. Anyway, just thought I'd ask to see if anyone might lead me to a good starting point.

 

[Andrew O'Neill]

Yeah, I've used 2:2:100 for HP5 for pt/pd printing. But, what I'd like to do here is: let's say the MDC indicates a developing time of 18 mins for Pyrocat-HD at 1:1:100; any stronger dilution will require less time, right? I'm also using minimal agitation, but I'm pretty sure I have that figured out. I really don't want to waste 8x10 film testing, but it may be the only way to derive the answer. Anyway, just thought I'd ask to see if anyone might lead me to a good starting point.

Yes, a stronger dilution requires a shorter time. Test with a smaller format if you can...say, 4x5. That's what I do. If any adjustments are needed, they are slight. Quite frankly, I've done all my 8x10 testing with 4x5 film, and haven't bothered to tweak for 8x10. I develop HP5 for 10:30 21C for carbon (EI 320).

 

[Alan9940]

Quite frankly, I've done all my 8x10 testing with 4x5 film, and haven't bothered to tweak for 8x10.

Thanks, Andrew. Yeah, I generally do all my 8x10 testing with 4x5, too, but in this case I have a stock of 8x10 that's no longer available in any size. I'm thinking I'll rig up my Rototrim so that I can cut one sheet into four 4x5; might not be so easy in the dark... we'll see.

 

[Ian Grant]

Alan, I processed my 10x8 films for 9 mins at 20ºC at 2 + 2 ro 100 when using dish development, that's compared to 15 mins at 20ºC 1 + 1 to 100 for 5x4 and roll films using inversion agitation ina Jobo or Paterson tamk/

Ian

 

[Alan9940]

Alan, I processed my 10x8 films for 9 mins at 20ºC at 2 + 2 ro 100 when using dish development, that's compared to 15 mins at 20ºC 1 + 1 to 100 for 5x4 and roll films using inversion agitation ina Jobo or Paterson tamk/

Ian

Thanks, Ian. Since I plan on using minimal agitation, I'm looking for a time longer than 9 mins but the MDC shows 18 mins at 1:1:100 for Acros 100 (original stock.) Using minimal agitation (every 2 - 3 mins), I'm probably looking at a development time of 24 - 25 mins. I'm using tanks & hangers and that's a long time to stand in the dark. Do you know what the effect is of going to a 1:2:100 dilution? Since B is the accelerator, I'm thinking this dilution would necessitate a shorter development time, but, perhaps, not as short as 2:2:100?

 

[Ian Grant]

Thanks, Ian. Since I plan on using minimal agitation, I'm looking for a time longer than 9 mins but the MDC shows 18 mins at 1:1:100 for Acros 100 (original stock.) Using minimal agitation (every 2 - 3 mins), I'm probably looking at a development time of 24 - 25 mins. I'm using tanks & hangers and that's a long time to stand in the dark. Do you know what the effect is of going to a 1:2:100 dilution? Since B is the accelerator, I'm thinking this dilution would necessitate a shorter development time, but, perhaps, not as short as 2:2:100?

Yes doubling the Carbonate will up the pH slightly and cut the development time but not that significantly compared to increasing both, maybe 20-25% less.

Ian

 

[Alan9940]

Yes doubling the Carbonate will up the pH slightly and cut the development time but not that significantly compared to increasing both, maybe 20-25% less.

Ian

That's very helpful info! So, doubling both to 2:2:100 would cut development time by 50% or in half?

 

[ProfessorC1983]

I believe that doubling B also increases the stain (at least according to my reading of the Sandy King article on P-HD) which would increase the UV blocking properties and increase the effective exposure scale for alt processes.

That said, I'm still using 1:1:100 for 24min in a steel tank with 4 inversions every 2min. That gives me a Dmax around 1.5-1.7, which with the stain factor should in theory give good DR for carbon... but admittedly I haven't made any prints yet to verify that hypothesis. If it's not high enough I may experiment with 2:3:100.

 

[Alan9940]

I believe that doubling B also increases the stain (at least according to my reading of the Sandy King article on P-HD) which would increase the UV blocking properties and increase the effective exposure scale for alt processes.

In my experience with HP5+, doubling B will most definitely increase stain. However, in this case I plan to print on typical B&W silver papers so I'm looking for a way to decrease development time while maintaining the overall stain of the 1:1:100 dilution. Based on Ian's input, it would appear that going to 1:2:100 will definitely cut development time, but by how much is unknow at this time. I will probably start my experimenting with the 1:2:100 dilution and see where it leads me.

 

[Andrew O'Neill]

You don't want excessive stain with HP5. More stain in the shadows and film base will block UV, resulting in very weak blacks.

 

[Ian Grant]

You don't want excessive stain with HP5. More stain in the shadows and film base will block UV, resulting in very weak blacks.

I use IT-8 an Ilford Toner, essentially it's a Dichromate.Bromide bleach like a Chrome Intensifier followed after a wash by a simple Pyrocatechin re-developer which oxidises very quickly. this gives wonderful olive black tone. Unlike other toners there's a slight intensification.

You might ask what has this to do with Pyrocat HD. In recent years as I always have Pyrocat HD on the shelf I've used it as the re-developer and it works just as well and has a better tray life. To keep overall staining of the background & borders to a minimum you need fresh developer and prolonged immersion in oxidised developer will greatly increase the background stain.

One advantage of using Pyrocat HD at 2 + 2 to 100 or more concentrated is with faster development the film or paper isn't sat as long in oxidising developer causing base staining.

Ian

 

[Andrew O'Neill]

I use IT-8 an Ilford Toner, essentially it's a Dichromate.Bromide bleach like a Chrome Intensifier followed after a wash by a simple Pyrocatechin re-developer which oxidises very quickly. this gives wonderful olive black tone. Unlike other toners there's a slight intensification.

You might ask what has this to do with Pyrocat HD. In recent years as I always have Pyrocat HD on the shelf I've used it as the re-developer and it works just as well and has a better tray life. To keep overall staining of the background & borders to a minimum you need fresh developer and prolonged immersion in oxidised developer will greatly increase the background stain.

One advantage of using Pyrocat HD at 2 + 2 to 100 or more concentrated is with faster development the film or paper isn't sat as long in oxidising developer causing base staining.

Ian

Interesting. I shall give 2+2+100 a go and see how HP5 fairs. Thanks!

 

[esearing]

One advantage of using Pyrocat HD at 2 + 2 to 100 or more concentrated is with faster development the film or paper isn't sat as long in oxidising developer causing base staining.

I tried this with Pyrocat HD and Pyrocat -M.
2:1.5:100 works too with minimal staining on paper. And to my eye the whole print becomes sharper perhaps due to alteration of edge contrasts. It can look muddy in the middle until full re-development occurs. The Metol version takes a bit longer for paper but is same for film.

For Film I mix more dilute and use longer time rather than shorter, so my negatives have a rich tan stain but also have less contrast that I boost during printing.

 

[Ian Grant]

The Metol version takes a bit longer for paper but is same for film.

Pyrocat HD and Pyrocat M aren't true equivalents for taht to be the case Pyrocat M would have a lot more Metol.

The ratio of Metol to Hydroquinone in D76/ID-11 is 2:5 in Pyrocat HD it's 2.5:50 Metol to Pyrocatchin

In Ilford Autopnen a commercial PQ version of ID-11 the ratio is 0.2:5 Phenidone to Hydroquinone now see how that matches the 2g Pyrocatechin and 20g Pyrocatechin in Pyrocat HD it's the same rartio of 0.2:5

So in Pyrocat M there's not enough Metol to be equivalent that would require 20gm which is a factor of 8x more. This explains the differences.

Ian