How much extra time for D-23 with benzotriazole?

I'm about to process an old (as in, a minimum of about seventy years old) roll of found Verichrome (the ortho version). The only dating I have is that this film was replaced by Verichrome Pan in the early 1950s, and this 127 roll is new enough to have the 4x4 framing track on the backing paper, which was not present until 4x4 cameras with red window advance came along after WWII -- so probably made between 1945 and 1952 or so. No, I have no expectations for images, but it's worth an hour and some chemicals to try it (and I can develop by inspection under red safelight to offset uncertainty on time, since I won't be using D-76, the only developer for which I know a definite time/temp for this film).

I had intended to use HC-110, but I found that several winters in a shed might have harmed my stash; next best is D-23, which I can run cold to minimize fog. I have some (unknown vintage) Kodak Anti-Fog No. 1 tablets, which I understand to be an unknown quantity of benzotriazole in each tablet; this is one of the strongest restrainers around, and combined with cold development in D-23 seems the best option other than HC-110 to get past the fog on this very old film to any images that might still be latent.

Compensating time for temperature is pretty easy -- a calculator with a power function will carry you as far as your developer's activity remains linear, and for a single-agent developer like D-23, that's down to "too cold to stay in shirtsleeves" temperatures. What's uncertain is how much time to add for the effect of benzotriazole (compounded by the uncertainty of how much is in each tablet).

At 68F, I'd expect D-23 stock to require about 25-26 minutes with normal agitation (allowing 50% more than the 17 minutes in D-76 that was standard for this film). Back the temp down to, say, 55F, and at 4% per degree, I'd need to develop for approximately 43 minutes with "normal" agitation (five inversions per minute). I don't look forward to that, but with a light jacket I can probably manage it. Question is, if I add a tablet or two of Anti-Fog No.1, how much longer do I need to expect (since inspection should preferably be done only after about half of development)? Add 20%? 50%? More?

The writer seems to know how much is in a tablet:

https://www.flickr.com/groups/67377471@N00/discuss/72157624036312130/

He says "Anti-Fog No.1 is not sold by Kodak anymore but it was simply a tablet that contained 0.45 grain (0.03 grams) of Benzotriazole"

I guess it would make sense for a tablet to contain enough for one film, and maybe one would not b enough in some cases..

Also, in

https://archive.org/stream/KodakReferenceHandbook/KodakReferenceHandbook_djvu.txt

I found this bit of text:

"Kodak Anti-Fog No. 1
Tablets (0.45 gr)
1 oz, 4 oz, 1 lb"

Developing old film is a trade-off. Less fog develops at lower temperatures but more fog develops the longer it sits in developer. A better bet, in my opinion, would be to use a stronger developer at a lower temperature. Benzo added to d23 might nearly kill its activity - I think I'd add alkaline, too.

Okay, open to suggestions. I have replenished Xtol (just about to replace it with EcoPro, and it's on the old side so I'd need to clip test to be sure it's still active) and Flexicolor Color Developer (same situation as the Xtol) already mixed, various opinions on how to make my HC-110 usable, and ingredients to make D-23, D-76, D-72, Caffenol, and anything that needs the same ingredients.

I developed some extremely fogged Kodak HIE that expired in 2009 recently using HC110 B. It was awfully fogged to the point that nothing was salvageable in the darkroom.

To compensate, for my next roll I added 6 drops of a 1% benzotriazole solution to my developer. Instead of developing at 20 C, I dropped the temp as low as I could reliably measure to (which was 15 C) and increased my dev time by 50%. The results gave me a much, much less fogged roll that gave me printable negatives. There was still some base fog, but it wasn't impossible to deal with. I bet if I drop the temp even further and add more time I could further reduce the fog.

So, I think your approach of using benzo with a lower temp and added time makes sense. I think you may have to experiment with different temps/times to get the optimal fog reduction you're looking for though.

Aviv said:

I think you may have to experiment with different temps/times to get the optimal fog reduction you're looking for though.

Click to expand...

That would be great, but there's just the one roll of this. When I get to my box of 4x5 Tri-X Ortho, I'll do some of that...

I would use something powerful: mix D-72.

Adding hydroquinone creates two problems: first, it is much higher fog than metol alone (or p-aminophenol), and second, times become non-linear near 60F, below which hydroquinone is reported to suddenly lose all or nearly all activity. I'd be more prone to add an auxiliary alkali to D-23, arrive at a baseline time by comparing clip tests, and expect that to get me close enough for DBI to finish the job.

Please do re-post to this thread to let us all know your ultimate choices, Donald, and how things turned out. Good luck!

Don, do you recall Gainer's "Perverted HC-110" ? The addition of a little TEA might get it all back into solution.

David Lyga put up a method of coping with old foggy film and basically used a high contrast HQ developer followed by an inspection bleach. Here on Photrio.

Murray Kelly said:

David Lyga put up a method of coping with old foggy film and basically used a high contrast HQ developer followed by an inspection bleach. Here on Photrio.

Click to expand...

Here we go: https://www.photrio.com/forum/threa...ts-of-age-fog-in-b-w-films-and-papers.161268/

Should be made a sticky thread.

Murray Kelly said:

David Lyga put up a method of coping with old foggy film and basically used a high contrast HQ developer followed by an inspection bleach. Here on Photrio.

Click to expand...

Ah, that's a good alternative, too. I've thought about inspection bleaching to control highlight clearing vs. Dmax in B&W reversal. First, of course, I need to get images that are distinguishable from base + fog.

I think I'm going to mix half a liter of D-23 stock with three Anti Fog No. 1 tablets (should be 90 mg of BZT) and add borax, do a clip test at 60 F (coldest my bimetal will read, and easy to get in my darkroom in winter) to get a time comparison to D-76 stock (I'll use a film that has current data for that) and use that to interpolate a "half development" for DBI under my red safelight.

Still not much hope for images on film that had to have been made seventy years ago -- but it's fun to try. Heck, maybe this camera I got on eBay was Mallory's and has a photo of him on the peak of Everest that will rewrite history. (doubtful, both camera and film are in better shape than I'd expect after 60+ years above 20,000 feet on a mountain).

I failed chemistry in school, and I've only ever used benzotriazole with old enlarging paper, but I do recall the more you add to the developer, the longer the processing time (at least for paper) to get the contrast up to an acceptable level, which for me somewhat defeated the entire purpose of using it.

in another thread you mentioned using old HC-110 with a similar film (or maybe the same film?). I posted comments there too.

To keep all this brief and to the point, consider using a higher contrast developer. And maybe do a clip test.

And please post when you have the results, even if it's a completely blank or fogged film. Bonne chance...

In fact, I probably should ask a mod to merge that HC-110 thread and this one, so I can put the results at the end of all this discussion. Let's see if that's practical...

Seriously, Don, I would suggest less BTA. That approach is a bit too much for film. Paper you can just do another one but for film I'd be more cautious.

Good luck t you for the one off experiment.

The amount of benzotriazole above was guessed from my memory of what was used in an article I've linked before about cold developing with restrainer added to salvage badly fogged film. I had to look back, he was using several drops of a 1% solution; call a drop 0.03 ml, and that would be about 0.3 mg per drop -- so three drops would be like two of the Anti Fog No. 1 tablets I have.

Donald Qualls said:

In fact, I probably should ask a mod to merge that HC-110 thread and this one, so I can put the results at the end of all this discussion. Let's see if that's practical...

Click to expand...

I think you will end up with an interleaved mess.
What I would suggest is put a link in each thread to the other thread, then ask me to close one, so that the continuing discussion can be in the other.
If you need a change to thread titles as well, just ask.

@MattKing Good suggestion.

Link to thread about crystallizing HC-110 (aimed at 127 Verichrome ortho): https://www.photrio.com/forum/threads/old-syrup-hc-110-with-crystals.189957/

That'll be the one to close, I'm going to try cold fresh mixed D-23 plus benzotriazole, either tomorrow night or on the weekend (depending how early I can get home tomorrow).

Okay, I mixed the developer today.

I made half a liter of D-23, then added 1 g (2 g/L) of borax accelerator (based in part on the Borax Accelerated D-23 formula here), and finished off with 1 tablet of Kodak Anti Fog No. 1 (0.45 gr = appr. 30 mg), which is twice the amount the instructions recommend for D-23 (1 tablet per quart). The developer is cooling now; this evening I'll clip a couple inches of Fomapan 400 from my bulk loader tail to get a time to compare to D-76. The reference time for D-76 stock for this film is 17 minutes at 20 C; I'll use the clip test time I get, relative to the D-76 stock time for the tested film, to obtain a time for the Verichrome.

Then tomorrow I'll chill everything as cold as I can go without having ice handy, apply temperature correction, and develop by inspection.

Okay, clip test completed. I clipped a piece of Fomapan 400 and dropped it into an open graduate (in room light) with 100 ml of my special D-23+borax+benzotriazole, and started a stopwatch.

The developer temperature was 72 F (22 C) and I judged completion by the emulsion side and base side reaching the same level of black (indicating all the milky halide had been developed). This took just under 3 minutes. After stopping the clock and washing the developer off the film, it looked like a good Dmax, quite black to the eye but the overhead room light was visible through the film without difficulty.

Now, the question is, how do I interpret that into a "normal" development with images on the film (short of shooting a test roll and developing that -- an option, but not one that'll get done in time to process the found film tomorrow)? D-76 stock should take (per Massive Dev Chart) 7-8 minutes at 20 C; correcting my observed time to 68 F/20 C would give 3 1/2 minutes. I don't envision this developer (no hydroquinone, appr. same pH as D-76, but with benzotriazole added) working twice as fast as D-76, so my presumption at this time is that I need to use the observed time to calculate an expected "normal" development time.

Or am I doing the entire clip test wrong, and should be watching for something other than reaching Dmax (something in the back of my mind wants to remember watching for first change and multiplying time by 5)? Whatever figure I come up with will be multiplied by 2.5 to get the final time anyway (D-76 is 7-8 minutes for Fomapan, but 17 minutes for ortho Verichrome).

Mind you, the result doesn't need to be high precision; just close enough that I can save any images that might get to that stage with development by inspection.

A supposed start time for developing an unknown film is doubling the time of a room-light clip test. So, from what you've done, you'd get a time of 6 minutes, then adjust that for temperature.

However, I think that will result in lousy negatives.

I'd cut off a piece of film and expose it in a camera and develop that for probably 12 minutes and see what the result was. You can't tell anything from a piece of film developed in room light, because it is massively overexposed and underdevelopment of the film will still result in opaque film. However, an image on the film will let you know immediately if you underdeveloped or overdeveloped it (when you're certain the exposure was correct).

Hmmm. Thinking whether I have a 35mm camera handy that isn't loaded. Okay, a couple -- two Nikkormats, my Discovery stereo camera, my Rollei 35 (there's a film transport problem, but the shutter's fine), my backup Kiev 4 body (slow speeds are slow, but above 100 it's close enough for this kind of test).

But... Temperature adjusted, doubling the full-black time would give 7 minutes, which is close enough to the same as D-76 to let me DBI (the target film here is ortho, and I have a pretty dim red safelight right, one I've used for printing for years, over my darkroom counter). This is a reasonable figure, since borax accelerated D-23 made without reducing the metol is essentially D-76H. I'll use the D-76 time and plan to inspect at 8-9 minutes, then adjust accordingly (unlike DBI with pan materials, I can keep the tank open and safelight on for the remainder of the development-- could do the whole job under the red safelight, come to that, but with roll film it's actually more convenient to be able to invert).

As you say, underdeveloped and massively overexposed film can be pretty black, but doubling the time is the factor I was forgetting. I'll be able to develop the Verichrome today, then, and ought to have at least a photo of the negative strip by this evening. Don't have a film carrier for 127 -- it's on the way from eBay -- but if I get my scanner cleared off I could lay a strip on the glass to get a half-ass scan.

Okay, the attempt has been made.

With success i'd be proud of if this were in fact Mallory's Everest camera and film! It's not; it looks (from the negatives) like either a kid's outdoor birthday party or a Cub Scout expedition, but there are seven clear, sharp, obviously printable/scannable images (the eighth frame is blank except for a halo that probably represents decades of light exposure through the red window). I'll have better images in a few days, but here's one where I had my cell phone much too close to the hanging strip, backlit by the overhead light in my darkroom with scatter from the very reasonable amount of fog.



I don't think this is a bad result for film that has to have sat in the camera since before I was born (and that's a bigger statement than it would be for a lot of the YouTube "I developed film from the 1980s!" crowd).

After leaving the bottles in the coldest spot in the house for several hours, I found the developer at 16 C (62 F), calculated my time at 23:30 with temperature compensation (confirmed for me by the temp compensation function in the Dev-It app I use on my Android phone). I inspected under red safelight at 12:00, decided at that time to inspect again at 18:00, and at 18:00 decided to stop development at 20:00. Standard acid stop, Kodak Rapid Fixer, Ilford wash, and C-41 Final Rinse (as that's the wetting agent I have mixed up), and the film is hanging to dry now. Despite the poor focus by the cell phone camera, the negatives look pretty sharp to my built-in magnification (-6.75 nearsighted prescription) -- probably about as good as one can expect from an achromat meniscus.

This is also the least exposed of the seven frames, so I'm looking forward to getting these scanned -- not to mention processing the new Rerapan I shot in this AVPK after I received it.

Looks good - hard to imagine it could look better, actually. Great job!