DTOD in Kodak D94A for motion picture film

AgX said:

Yes, but as an amateur one can run a replenoshed process too. Or one just can add starter at each run and discard the baths after this. The issue with the Kodak offer is just the sheer size.
For amateur volumes reversal kits, yout got in Europe quite some choices: Adox, Bellini, Foma, Wehner.

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To the first part of your answer, good point. I understand replenishment process, but good to have this reiterated. My confusion is that the kits mention a starter without mentioning a developer, and replenisher without mentioning working solution to replenish. Are the working solutions included?

Regarding the second part of your answer: Good to know. I have used the Foma reversal kit with Fomapan R100, but was not sure how well it would work with Trix 7266. Do you know, offhand? I will look at the other kits, as to their availability in the US.

Pakman777 said:

My confusion is that the kits mention a starter without mentioning a developer, and replenisher without mentioning working solution to replenish. Are the working solutions included?

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At a replenishing kit there is no developer in the proper sense. To avoid another unnecessary concentrate in larger volume, a smaller volume concentrate is part of such kit.
By adding a small amount of this concentrate to the replenisher you get the developer concentrate you are used to as amateur.
Only if you do not discard the resulting developing bath after a run (runs), but want to replenish, you add to this bath some replenisher after each run.
Thus at a replenished proces you only once need a starter, from then on you add and add just replenisher. Only if such proces runs out of tolerance, you have to make a new batch, with a bit of starter.

AgX said:

At a replenishing kit there is no developer in the proper sense. To avoid another unnecessaty concentrate in larger volume, a smaller volume concentrate is part of such kit.
By adding a small amount of this concentrate to the replenisher you get the developer concentrate you are used too as amateur.
Only if you do not discard the resulting developing bath after a run (runs), but want to replenish, you add to this bath some replenisher after each run.
Thus at a replenished proces you only once need a starter, from then on you add and add just replenisher. Only if such proces runs out of tolerance, you have to make a nw batch, with a bit of starter.

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Thank you! This is extremely helpful for me. Thank you for clearing up my confusion.

I was curious about Kodak's new reversal chemicals and a search took me to this thread. Although the thread is a bit old, I wanted to mention a recent experience related to B&W reversal processing.

I processed B&W reversal film 40-50 years ago using the chemistry recommended at the time. The principle of reversal development is quite amazing in its simplicity, and it really doesn't require special "reversal" film or developer - just the extra steps of bleaching, reexposure and redevelopment.

BUT, obviously, companies like Kodak go to extreme lengths to develop emulsions and chemistry that will optimize the experience! There's really no reason in 2023 for B&W reversal film to even exist, but it seems Kodak (and others) have gone out-of-their-way to keep this system alive.

But the reason I'm writing is what happened when I sent my B&W reversal film to "The Film Photography Project" for developing. FPP seems to have a closed-loop monopoly right now on 16mm magazine film, which is an interesting format because you can buy a functional 16mm movie camera for about $25! Also, the film cost less than 100' rolls, simply because there is only 50'.

I thought the development provided through FPP was absolutely horrid. In addition to being very scratched, filthy, and spotted, there was some "unevenness" in the light/clear areas, which I called "mottling' but Michael at FPP called "staining." I pulled out some B&W reversal film I had processed in 1972, and it didn't have this problem at all! It wasn't scratched either, and not nearly as dirty.

Michael at FPP refuses to say who processed my film or what method was used. Or even what company made the ISO 40 reversal film! (Or if it even really was reversal film!) But after skimming this thread, I wonder if the company that processed the film wasn't using the latest developer or bleach. It seems that if you bleached the black silver imperfectly, you might get the unevenness I'm seeing in the image.

I will say, the combination of these flaws makes the film look EXACTLY like it was processed 100 years ago! Which actually works, if inadvertently, for my project. But if you are trying to get a modern B&W look with subtle and gorgeous tones, FPP might not be the place to go.

Here's a look at my movie, edited to 52 seconds. (Shot at 16 fps, FPP uses a 1/2 pulldown to make 24 fps video):


--Gary Davis
Los Angeles

gdavisloop said:

The principle of reversal development is quite amazing in its simplicity, and it really doesn't require special "reversal" film or developer - just the extra steps of bleaching, reexposure and redevelopment.

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well, while we can process pretty much every b/w film as negative, there are reasons to use film and chemistry optimized for it, specially if you plan to project:
Films with a clear base and high DMax will give more brilliant images, and so will developers with higher than normal contrast and silver solvent added.

adding to the original question of the thread:
DTOD in D-94A is indeed a silver solvent and replacement for Thiocyanate as mentioned by others.

from what I've read it's been changed because Thiocyanate could react to Cyanide in the new permanganate bleach (R-10), which is a very strong deadly toxic even in smallest quantities.
so use D-94A with the new beach R-10.

Unfortunately R-10 needs a lot more care to get consistent results than the older R-9 dichromate bleach.

I've been processing Super8 reversal film for 30 years, never had a problem with R-9 (using D-94, D-19 with Thiocyanate, or Dokumol with Thiocyanate), the last 5-10 years I've been using R-10 and it took me many tests to get reliable results.

I have managed to order DTOD and Permanganate through my local pharmacy.

hope that helps

>Unfortunately R-10 needs a lot more care to get consistent results than the older R-9 dichromate bleach.

Given that the film I sent to FPP was "bleached badly," I'm curious what problems you were having, and how you resolved them - thanks! --Gary

gdavisloop said:

>Unfortunately R-10 needs a lot more care to get consistent results than the older R-9 dichromate bleach.

Given that the film I sent to FPP was "bleached badly," I'm curious what problems you were having, and how you resolved them - thanks! --Gary

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Mainly the trouble was to get uniform, complete bleaching. The key is to use constant agitation and sufficient bleach time.

There also have been reports of stability issues with the permanganate solution. I never encountered that, but I probably am over cautious, mixing the bleach with demineralised water and only using it for one session.

I use R-10 from the Kodak reversal process:

dokko said:

There also have been reports of stability issues with the permanganate solution.

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Permanganate solutions are notoriously unstable. They tend to deposit manganese oxide on the inside of the vessel and this in turn acts as a catalyst for the process, so it's actually auto-catalytic and will accelerate over time. The process is further accelerated by low pH (acidity), heat and UV. Using demineralized water to make the solutions may help very slightly, but won't make the solution immune to degrading over time. I've had permanganate solutions 'go bad' (i.e. most of the permanganate reduced to some form of manganese oxide).

koraks said:

Using demineralized water to make the solutions may help very slightly, but won't make the solution immune to degrading over time.

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My aim here was less to improve long time storage, but to make sure that water impurities don‘t influence the effectiveness of the fresh solution.
Kodak lists Calgon S in it‘s R-10 formula, I suppose that serves a similar purpose. I actually add this even to demineralised water, hoping that it also helps against gelatine swelling and softening (which can be another problem). To clarify, I have no evidence that it helps in this regard but it seems to me that it can‘t hurt

I‘ve read some reports that the Calgon should help against degrading over time, but never from definite sources and I‘ve never ran any conclusive tests on that myself.

dokko said:

I‘ve read some reports that the Calgon should help against degrading over time, but never from definite sources and I‘ve never ran any conclusive tests on that myself.

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Well, sodium hexametaphosphate will help, but the bleach will degrade within weeks and become too ineffective. I don't remember the exact timespan it's been years since I tried this. And this was with 20g/l, or whatever Agfa used in a patent.

EDIT: The pdf you linked to in a previous post gives a 1 week storage life for the mixed bleach. This might be a bit conservative, but certainly not far from my observation. IIRC, it was basically useless after 3 weeks.

dokko said:

My aim here was less to improve long time storage, but to make sure that water impurities don‘t influence the effectiveness of the fresh solution.

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Makes perfect sense! I was just adding my comment to clarify that the instability of permanganate solutions is really inherent to the concept.
I agree that the added sequestering agent won't hurt in any case. I don't think it'll do anything to protect the emulsion, though. Permanganate is just a little aggressive. Again, it's inherent to the stuff itself.