Adox CHS 100 II in Pyrocat HD?

[Peter Yeti]

I finally got my first box of Adox CHS 100 II delivered and can't wait to try it out. One of my standard developers is Pyrocat HD and I use a Jobo processor. Does anyone here has first experiences with that combination? I'm looking for a first hint for the development times.

Alternatively, does anyone know how old and new version differ in various developers? That could give an idea for a start as well.

Thanks for any info.

[Domingo A. Siliceo]

Hi Peter.

I'm in the same situation than you, but my box of Adox CHS II will remain closed until I finish the Fomapan 100 box. Anyway, I use a Combi Plan tank to develop.

So little information in the "cloud", but my first guess for developing times using Pyrocat-HD 2:2:100 will be 10 minutes.

Sorry I can't give you any proved information.

[brucep]

My reagents for making up some Pyrocat arrive tomorrow, and i plan to shoot some 5x4 this coming weekend to run some tests next week.

Any starting point info would be more than welcome.

Bruce

[Peter Yeti]

Hi Domingo,

Thanks for your first guess. I found some data on digitaltruth.com and it seems that CHS II is quite similar to the old CHS or reacts a little faster. Since the old data was 8 minutes, my first guess for CHS II would be 8 minutes as well. I'm surprised that nobody here tested this yet, given the popularity of the old efke stuff, which was the same as Adox CHS. I'm afraid, we have to test from scratch.:-(

Peter

[Andrew O'Neill]

As an avid Pyrocat-HD user, I will be looking forward to hearing your results.

[Peter Yeti]

Hi all,

Since it seems that nobody tested this yet, I started basically from scratch and sacrificed my first sheet. I used my standard setup for this: a white wall, a studio strobe, a Gossen Spot-Master, and one of my 4x5" cameras with the Apo-Sironar 5.6/210 attached set at infinity. The light is adjusted to give zone V at f16 and then I expose zones I-IX on one sheet by multiple exposures pushing in the dark slide step by step.

For this first test I assumed ISO 100, mixed Pyrocat HD 5:5:260, and developed 8 minutes @ 20°C using a Jobo CPE-2 at rotation speed 1 and a 2521 drum with 2509n reel. At first glance it already looked promising. The sensitometric an densitometric measurements more or less confirmed the first impression. ISO 100 seems pretty reasonable, zone I is at least 0.11 and at most 0.23 above base level. Unfortunately, I didn't leave enough edge to measure the base precisely. Gamma using all data points is between 0.61 and 0.65. A pronounced S shape of the density curve is quite noticeable and fairly typical for classic films like the old Adox. I attach a graph of the measurements here:



For me it looks like the new stuff reacts pretty much like the old stuff (hopefully without all the crappy defects). Next I'll have to test it with a real picture to check that it's really doing what I want it to do. Hope this will give y'all a good starting point as well.

Peter

[Peter Yeti]

Hi all,

I took the next step in testing and things look promising. I put together a quick table top with enough contrast to sample a typical N development scene. Obviously, I didn't waste much effort for optimizing the lighting for the still but I made sure that zones II-VIII are present. Here is a simple negative scan straight from the scanner without manipulating curves:



Separation in the shadows could be a bit better. On the light box it's there. I measured on the tight side for the test so I will be on the safe side when I use the film. According to this, EI might be slightly lower than 100 if I want some leeway. Lights are far from being blocked, so there is room for increasing contrast I suppose. I still need to make a real silver print to get a more reliable idea of the practical contrast.

Peter

[Andrew O'Neill]

I would probably shoot it at EI 64-50.

[Peter Yeti]

Could be, did you try it? Density values indicate that 100 is right. It could be easily that personal perception during the metering calls for rating it lower. I still hope that some others will share their personal experience here...

[Andrew O'Neill]

If it prints well on a "normal" grade of paper, then EI 100 will stand. Your testing is appreciated!