Adox CMS 20 - adventures in development Part Two

This is Part Two of Scotty Elmslie's experiments to find a conventional developer capable of producing good results with Adox CMS 20 II document-type film. If you haven't already done so, please read Part One or you'll be all at sea.

CMS 20 II – Test to determine ISO and development time

by Scotty Elmslie

Third Roll

Exposed at ISO 12/10/8 and developed in Rodinal 1+119 (2 + 238 ml) for the equivalent of 20 minutes at 68F, closer to traditional stand development. Rodinal is sufficiently active that I didn’t think I needed to do this in a 500 ml tank (4+496) since the whole point is to exhaust the developer at the film surface to limit the highlights.

Agitation was gentle for 5 seconds, once after 10 minutes. Unfortunately, this was not enough agitation. The developer appeared to bleed from the clearer (shadow) areas in the negative down into the denser (lighter) areas (the sky was at the bottom of the reel). It also bled in from the clear, unexposed edges. Even with this dilution, the contrast was excessive.

ISO 8:

Fourth Roll

Exposed at ISO 10/6/4 developed in Rodinal 1+119 (2 + 238 ml) for the equivalent of 13 minutes at 68F with 15 seconds initial agitation and 5 seconds every 4 minutes after that.

At ISO 6 the shadow detail is still not rendered properly. The reduction in development is getting closer to normal contrast but it is still too high. However, the agitation was insufficient and the thinner portions of the negative still bled unexhausted developer into the darker negative (lighter print) tones. When I do a fifth roll I will probably use ISO 6 since this is the normal low limit for 35 mm cameras. It will require more frequent agitation and shorter development, around 10 minutes.

ISO 6:

Conclusions

The good news is that, as advertised, it is an extremely fine grained film that can be used to make huge enlargements. It probably exceeds the resolution of most conventional lenses. It is possible, with some effort, to get it to render a pleasant range of tones from moderately dark to very light without blowing the highlights. CMS 20 is fine where the subject is low in contrast or where you don’t mind letting the shadows block up.

On the other hand, there are several more conventional films available that have grain that is nearly as fine, are easier to develop and whose true ISO (at 0.1 above film base = fog) is much higher.

Even ISO 6 may be overstating the film speed. To keep the contrast from getting out of hand, development needs to be so gentle that the shadow details and textures simply cannot be brought out. Deep shadows remain blocked up and cannot be coaxed into revealing texture. Insufficient agitation leads to bleeding of active developer and loss of sharpness.

It may be possible to get some form of normal development between ISO 12 to 20 using Adox Adotech developer. But I am not interested in spending $26 on a bottle that can only develop six rolls to find out. 

I would not recommend CMS 20 with low-light or high contrast situations since reciprocity will be hard to determine and control. The only thing I suggest in these cases is that you bracket your exposures. That’s OK for 35mm but it may be extravagant for medium and large format.

While CMS 20 II might provide some benefits for 35mm photography, medium and large format users are better off with TMax 100.

…………….

Bruce writes: A couple of years ago, I thought CMS 20 could be something of a wonder film and set up a Flickr group to encourage people to post their results. If you want to see some pics using this film then please visit the group at https://www.flickr.com/groups/1444945@N21/.

I kind of lost interest in CMS 20 for the reasons I wrote about in Part One. I know other photographers have tried the film with varying degrees of success over the years. If you've cracked it or know of someone who has then please let me know about it by email.