PDA

View Full Version : Stain with Pyrocat HD in higher dilutions



mgeiss
7-Jan-2014, 00:11
Hi there and a happy new year!

I'm experimenting with higher dilutions of Pyrocat HD for lith film. 1+1+200 works fine, but when I tried 1+1+300 yesterday, I got a massive increase of stain. Is this to be expected, and could I achieve less stain by altering the A-B ratio?

I would also like to try the devided variant in higher dilutions. Does anyone have experience with 1+50 A and B compared to the normal 1+10 or 1+20?

Jim Noel
7-Jan-2014, 09:35
Why don't you do the testing and let us know the results?

mgeiss
7-Jan-2014, 09:39
I will, Jim ;)
But it's always good to have some starting points or experiences before "wasting" developer.

onnect17
7-Jan-2014, 17:25
Mattias,
The standard dilution is 1:1:100 and not less than 300ml per 80 square inches with small tank development. If using constant agitation, like a film processor, where oxidation increases then you should use a dilution of 1:1:50 or lower.

So to answer your question, your should obtain similar results with 1:1:300 diluton if using 50% more solution.

You can visit pyrocatHD.com and PM Sandy if you still have other questions.

sanking
7-Jan-2014, 17:36
Hi there and a happy new year!

I'm experimenting with higher dilutions of Pyrocat HD for lith film. 1+1+200 works fine, but when I tried 1+1+300 yesterday, I got a massive increase of stain. Is this to be expected, and could I achieve less stain by altering the A-B ratio?

I would also like to try the devided variant in higher dilutions. Does anyone have experience with 1+50 A and B compared to the normal 1+10 or 1+20?


Some films, TMY for one, tend to give a lot of stain when used with very dilute Pyrocat-HD solutions. If the additional general stain is a problem it can be reduced by increasing the amount of Stock A compared to Stock B. For example, in my own work with higher dilutions with minimal agitation and semi-stand I use a 1.5 + 1 + 150 dilution, sometimes 2 + 1 + 200. You could also experiment with adding a bit of ascorbic acid to the working solution as this will slow solution oxidation, which causes stain.

For some time I have been doing virtually all of my development with two-bath Pyrocat. The dilution, along with time and temperature, dermines how much reducer the gelatin of the emulsion can absorb, and the more it absorbs the higher will be contrast. Time and temperature of the solution also play a role, but the dilution itself is the major determinant. I have found dilutions between 1+5 to 1+20 in the range of feasible and practical. Dilutions greater than 1+20 will give very low contrast and low film speed.

Here are some general guidelines with two-bath development that apply to developers where no activity takes place in solution A. This applies to Diafine as well as Pyrocat-HD.

There are three ways to control the amount of reducer a given film can absorb, listed in decreasing order of efficiency.

1) Increase or decrease the concentration of Solution A. Using a weaker dilution decreases final contrast, a strong dilution increases contrast. For example, a 1+10 dilution will give negatives of higher CI than a 1 + 20 dilution, all other things being equal.

2) Decrease or increase the temperature of Solution A. A temperature of 80F, instead of the recommended 75F for normal development, will allow the gelatin to swell more, thus increasing its ability to imbibe reducer, thus increasing slightly final negative contrast.

3) Increase time in Solution A. Longer soak times up to about six minutes, other things being equal, will usually increase the contrast of the negative. However, increasing time in Solution A carries with it the risk of staining.

In practice the most effective way to change contrast is to increase or decrease the concentration of Solution A and hold the temperature constant at 75 F and the time in Solution A and B at a minimum of 3 + 3 or a maximum of 5 + 3.

Since the final contrast of a negative developed in a two-bath developer depends primarily on the amount of reducer it can imbibe in Solution A we should expect some variation in the actual CI of films unless we adjust one or more of the variables that determine how much reducer the emulsion can imbibe. In general there are three ways to control the total amount of reducer that a given film can absorb.

Sandy

mgeiss
7-Jan-2014, 22:24
Mattias,
The standard dilution is 1:1:100 and not less than 300ml per 80 square inches with small tank development. If using constant agitation, like a film processor, where oxidation increases then you should use a dilution of 1:1:50 or lower.

So to answer your question, your should obtain similar results with 1:1:300 diluton if using 50% more solution.
I think that the amount of solution (or concentrate for that matter) was enough. I developed one test sheet of 4x5 in 750ml of 1+300 solution.

Sandy,

thank you for your detailed answer! For this special purpose, having very low contrast should be fine. The film is Wephota FO5, which shows a range of about 2 stops in 1+100 and 3-4 stops in 1+200 with 10 minutes of development. Developing shorter doesn't lower the contrast much, because the film builds up density very fast. Lowering the agitation to less than once per minute doesn't help either, because this leads to uneven development with this film, even when i pre soak and use a bit of photo-flo in the solution.

When i used 1+300, the contrast was good, but the negative looks like it was build of stain and not silver :)

I will test the devided variant with constant rotation in a Jobo Expert drum. I'll start with 1+50 and 5 minutes in each bath, to get a starting point. Of course that may lead to unusably low contrast with normal films, but the FO5 may come out fine, as i'm looking for very low contrast (comparable to the results with POTA) anyway.

I will keep you updated, when I have tested some dilutions/times.

onnect17
8-Jan-2014, 09:25
Mattias,
1:50 is too little for two bath, I think. It's better 1:20 or higher concentration.
You should also avoid the 3010 tanks on a rotary base with this developer.

mgeiss
8-Jan-2014, 10:16
I don't have a 3010 but the 3005 and the 3006. Both work fine on my motor base with divided Pyrocat. 1+20 works fine for me with normal films, but the FO5 gets too contrasty in managable times over 3 minutes in A and B. Think of it as a Technical Pan but much harder. :)

You may well be right, and chances are, I'll end up with a 1+30 to 1+40-ish dilution and even then don't get continuous tone out of the film. But I want to try to get the best out of the developer I have on hand, before mixing a special low-contrast developer, for which I don't have much use with my everyday films.

rcmartins
8-Jan-2014, 15:53
Just wanted to clarify that Wephota FO5 does not require a low contrast developer. I use print developers (Neutol NE and Dektol) regularly with it and control the density from 0.1 to 4.8 with no problem, but then also with no stain. My comment is not to put you out of your quest for a stainning developer for Lyth films. On the contrary, I am following this thread with interest as I would also like to learn the behaviour of this extremely thin film with PyrocatHD which I use with regular films.
raul

mgeiss
8-Jan-2014, 21:43
Raul, using a diluted paper dev or even the C41 dev for high contrast films is a common technique (and could be called a low-contrast developer), but I didn't try that yet. Which dilution of dektol are you using? I assume you develop by inspection?

rcmartins
9-Jan-2014, 01:41
True although I don't consider Neutol or Dektol low-contrast developers and I brought them in because print developers are readily available, most photographers have them for printing, and are in fact a common approach for developing these films. The dilutions I use for Dektol range from 1+39 to 1+1 while with Neutol NE I go from 1+59 to 1+9. Also, I change the agitation amplitude and frequency and the development time. My development times range from 70 s to 180 s at 20C. Yes, I develop it in trays by inspection.
By the way, when you develop it in Pyrocat do you prewash it? This film has a very strong red anti-halation layer that takes quite the beating to remove during tray processing and becomes a nuisance when I go for low-amplitude and low-frequency agitation schemes if I don't prewash it. I don't know how much of what I see coming out of the film in the early stages of development is bromide and how much is residue of the anti-halation layer, but there is a lot of stuff coming out :)
raul

mgeiss
9-Jan-2014, 01:46
I don't pre-soak the film, but I will for the two-bath development. I develop by inversion or by rotation, never in trays (I just don't like it :) ). The anti-halation layer comes off sometime during development, and the film base is nearly crystal clear when i pull it out of the final wash.