Adox CHS 25 in 8x10 - pyrocat HD development

[Dave Tolcher]

Hi there, I need some advice please on dilution/dev time/film speed for Adox chs 25 in 8x10.

Just started a box of this, developed first 4 sheets as per the Massive Development Chart advice - rated at 25 asa, 2:2:100 dilution for 10 minutes with agitation for first minute then 5 sec per minute thereafter. Developed in a modified Paterson Orbital. Negatives look good but with a bit more contrast than I perhaps expected for the shooting circumstances (flat light).

My use of pyrocat previously had been at 1:1:100 with Fomapan 200 rated at 160.

Is my thinking sound that I could reduce film speed to say 18 and use 1:1:100 for about the same time and this should give me a less contrasty negative ? I am looking for a negative that I will scan and contact print.

What are other folk doing ?

Thanks

[Regular Rod]

First of all congratulations on possessing some Adox CHS 25 in 8x10 !!! (I'm in breach of the Tenth Commandment here...)

Do you make up your own developer from raw chemicals?

If so you may like to try OBSIDIAN AQUA, using it as a compensating developer with a mild semi-stand routine for agitation to control the contrast.

Here's the formula (Catechol and Pyrocatechin are the same thing): http://freepdfhosting.com/aa330a94ce.pdf

This pdf has a semi-stand routine that leads to consistent results via a modified Paterson Orbital: http://freepdfhosting.com/f640343f29.pdf

RR

[Dave Tolcher]

Thanks Rod, a precious 2 boxes....

I haven't gone down the raw chemicals route preferring the pre bagged versions from photographers formulary at this stage. Daft really as I did a phd in synthetic organic chemistry ! Looks interesting & I haven't come across that one before.

[Regular Rod]

Thanks Rod, a precious 2 boxes....

I haven't gone down the raw chemicals route preferring the pre bagged versions from photographers formulary at this stage. Daft really as I did a phd in synthetic organic chemistry ! Looks interesting & I haven't come across that one before.

It's dirt cheap to make. I got my chemicals via eBay, including the distilled water. The dilution is so tiny. 1ml A, 12.5ml B, made up to 500ml with tap water makes it economical. The stock solutions last indefinitely. It doesn't seem to go off at all.

RR

[IanG]

I still have 3 boxes of 10x8 CHS 25 I shoot it at 50EI have done in all formats since the mid 1970's, it's 25 ISO in Tungsten light not daylight. I process in Pyrocat HD 2+2+100 for 9 mins @ 20ºC in a tray similar agitation.

Ian

[Dave Tolcher]

Thanks Ian

[Regular Rod]

You can't beat this forum for quality, first hand information and assistance on just about anything to do with our branch of photography!

Oh and Ian, that ground glass you made for my whole plate camera is utterly perfect!

RR

[Jim Fitzgerald]

I have 7 boxes of Efke 25 in 8x10. Also one box in 11 x 14. This was my main film. I am fortunate to have some in 8 x 20 as well. I have always used Pyrocat HD with this film.
I use 2:2;100 normal agitation for 7-12 minutes depending on field notes. Now I am a carbon printer and this film gives me a full range negative when I get it right.
I develop by inspection and I know what my negative needs to look like for my carbon printing.
I have always mixed the stock solutions from scratch which makes this a very inexpensive developer for me.

You can try minimal agitation at 1.5:1.5:100 and increase the time to 15-18 minutes with agitation once every 3 minutes after an initial agitation of 1.5 minutes to start. Works great to compensate. My best negatives were developed this way. I do my 8x10's in a dip and dunk tank and the ULF negs in trays.

Hope this helps. Look up develop by inspection and try it. Takes some time to figure it out but I never worry about temperature and the times I gave are guidelines. You can see when the negative is done!

[Dave Tolcher]

Thanks Jim, I am without a darkroom at the moment but your suggestion sounds like a good one when we move permanently. I will try the compensating protocol you suggest, I can see that would work well and wondered how you might do that. I used to 2 bath with pmk or dixactol and have tried borax bath with varying degrees of success. Are you at 25asa ?

The good news I found another box in the freezer so that will keep me going for a while.

Best regards

Dave

[Jim Noel]

Hi there, I need some advice please on dilution/dev time/film speed for Adox chs 25 in 8x10.

Just started a box of this, developed first 4 sheets as per the Massive Development Chart advice - rated at 25 asa, 2:2:100 dilution for 10 minutes with agitation for first minute then 5 sec per minute thereafter. Developed in a modified Paterson Orbital. Negatives look good but with a bit more contrast than I perhaps expected for the shooting circumstances (flat light).

My use of pyrocat previously had been at 1:1:100 with Fomapan 200 rated at 160.

Is my thinking sound that I could reduce film speed to say 18 and use 1:1:100 for about the same time and this should give me a less contrasty negative ? I am looking for a negative that I will scan and contact print.

What are other folk doing ?

Thanks

All slow films are inherently more contrasty than their faster cousins. Reducing your EI won't help with contrast. If you like less contrast in your negatives, reduce development time, or developer strength, and or agitation.