J&C Pro 100 -- any progress?

[Donald Qualls]

From our experience with Efke film we know that pinholes sometimes occur when using acid fixers. This is why we recommend a water stop. The other important factor is development temperature. If you go past 68 degrees with these soft emulsions you run the risk of emulsion lifts and holes. You can be a lot more abusive to a modern film and get away with it. We have had several instances of people having problems and writing us that "I do the exact same thing with Kodak this or Ilford that and I have no problems". Once the process is refined to be less severe the problems go away.

I've been able to start processing at 68 F during the winter months, but during summer it can be a challenge to lower the developer, stop, and fixer temeperature enough. Hopefully I'll be able to find a cool location in which to store my chemicals and water jugs once we start up the air conditioning, and be able to work at the proper temperature (last summer, in a house without A/C, I developed a fair amount of film at 75 F, but that was Kodak, with a harder emulsion).

Do you have any information on possible benefits of either a hardening fixer or pre-hardener (before developer)?

Edge fogging is a problem with many films. The paper itself is opaque and does not leak. The streaks are from the edges of the film with light piping down the clear polyester base material. Some films use a gray base instead of clear and this seems to minimize the piping problem. However, you now have a gray base which has it's own problems for some people. The classic phrase "load in subdued light" applies. We are now including the plastic film canisters with each roll of Pro film. So if the film is loaded and unloaded in subdued light and kept int he black plastic canisters there should not be any problems.

I've always kept my paper-backed film out of direct sun, and never had a problem with edge fogging unless I had a roll that had gotten misaligned. I do, however, greatly enjoy the black cannisters -- they also work very well to protect film respooled to 620, which of course is no longer in the original wrapper, and to protect the 620 spools from damage when empty. I have a number of similar tubes I've used for my 620 spools, but they are translucent, and not much help for film that's been opened for respooling or exposed. I'd buy a bunch of those if they weren't coming with the film -- IMO, they put the Pro 100 ahead of even the .EDU sold for the same per-roll price, because the cannister adds value.

I have PM'd the poster regarding the scratch issue posted above for more information. Nobody else has reported this as a problem before. Has anyone doing 4x5 with this film seen it? Once again, while scratches from the factory certainly are possible and have happened before our experience with these old style films is that usually the emulsion gets scratched somewhere in the developing process.

I have two packets of the miscut 4x5 that I will be using soon in pinhole cameras -- I'll certainly post back here if I see similar problems; since I develop my sheet film in tubes, nothing but liquid touches the emulsion side of the film. I don't know that this oldest stock will tell much about the current state of the coating, however.

 

[jd callow]

The second report came from the owner of a local pro-lab who showed me a suspiciously looking similar problem that he's seen occurring with Ilford's XP2 Super B&W CN -41 film (more visible on 16x20's from the 120).

It seems certain that with the Efke, the culprit was highly acid stop bath, and is most likely the same cause with the XP2. The pinholes on the XP2 are a fairly recent problem that have begun to come up on other discussion groups, so I suspect that Ilford has made some unanounced manufacturing changes, with pinholes being the end result.

I don't know if that was more than .02 cents worth or not!

I would be surprised if the lab used a stopbath with their c41 process.

 

[doughowk]

I've used both 120mm rolls & 4X5 sheets and have not noticed any pinhole problems. I develop in Rodinal 1:50 for 13.5 mins & use a water stop bath in combination with TF-4. In my experience, it may be slightly slower than Efke 100, but has good contrast; and I've gotten some very good images with it. Plan to use it with my 8X10, and its price makes shooting in the larger formats very affordable. Thanks J&C.

 

[rjr]

I would be surprised if the lab used a stopbath with their c41 process.

Tetenal recommends a Stop bath with their C41 kits and IIRC Kodak does the same.

But nevertheless, an acid stopbath is rarely ever the reason for the mentioned Pinholes - none of us is using deep tanks to process films in and only with these pinholes can occur (due to hydrostatic pressure and only when the developer contained lots of carbonates.

 

[Donald Qualls]

But nevertheless, an acid stopbath is rarely ever the reason for the mentioned Pinholes - none of us is using deep tanks to process films in and only with these pinholes can occur (due to hydrostatic pressure and only when the developer contained lots of carbonates.

There is another mechanism whereby acid stop bath could cause pinholes, even in the absence of carbonate alkali. With soft emulsions, the emulsion can change condition enough, and do so rapidly enough, when it transitions past the isoelectric point (from alkaline to acid or vice versa) to cause significant shrinkage or swelling; if the emulsion weren't perfectly bonded to the base in a small region, that expansion/contraction could cause local stretching and even perforation that would resemble the bubbles and pinholes we've seen with the Pro 100 film.

My next roll (or sheet, if I get around to exposing some of the 4x5 before I finish another roll in my box cameras) will get processed with water rinse instead of stop bath -- and if I still see pinholes, I might also try alkalizing some fixer (by adding ammonium hydroxide, aka household ammonia, to neutralize the acetic acid) for the roll after that.

This film is good stuff if we can beat the problems -- and the problems seem similar to what's been seen with Efke soft emulsions, so the same things (more careful temperature control, elimination of alkaline/acid changes, and great care to avoid mechanical contact with the emulsion when wet) should solve the problems.