As annoying as it is, I kind of like the idea that some of these things remain mysterious after nearly 200 years of photography!Appears from FDC p131 that Bill Troop spoke to TH James about the fogging problem and James said that its growth is never predictable. That was the situation in 2020, the only new thing I can add is that I managed to get some fog with Fuji Eterna RDS 4791 low ISO film in CD4-LC. Fog is thus not confined to phenidone and remains unexplained IMO, except that both phenidone and CD4 form oxidation products that block the emulsion surface.
Oooh interesting. Did you also happen to try any in a pre-bath without photoflo? Maybe I'll do that myself in a little bit.In the last attempt with H&W Control and Imagelink, I got something interesting - an overdeveloped negative (really a lot), but almost no fog. In it's test I had a pre-bath with some photoflo.
Ooh, interesting. I have indeed been using anhydrous. I'll have time later this week to try again, so I'll reduce the carbonate down to 3.83g. I'm very lucky that someone else is playing around with this film/dev who actually knows what they're doing re:chemistry!I did another series of experiments and found some things.
First, the key in this developer is pH. For some reason, I'm getting a higher pH than it should obviously be. In this regard, there is an omitted detail in the formula - sodium carbonate is not anhydrous, but monohydrate. This requires an adjustment to the amount if you are using anhydrous. For pH, I aim for 9 - 9.5 (max).
For even development, shake the first 1:5-2 min constantly, then every minute. Not violent, but slow stirring.
It appears that low pH results in low contrast, little grain, and low base fog, and high pH results in high contrast, high amount of fog, and coarse grain.
Also something important - at high pH above 10.5 I get dichroic fog! It appears to be related to the phenidone.
Hey, sometimes we luck into some weird film and want to get the most out of it! I'm mostly an HP5/HC-110 guy, but I am irrationally fascinated by hi-res films. I also find the unperforated aspect of the Imagelink really intriguing, since it opens up a bunch of interesting non-standard formats for potential DIY cameras. 30x30 square or 30x60 pano, to name two. And, of course, I am totally, definitely going to get around to building said cameras.I hope you are keeping good notes.
I'd use the K.I.S.S. and try one film and one developer at a time. There is nothing really special about micro-film except that with any developer you have to drop the film speed and increase the development time. Each of these need to be varied by running controlled tests. That's much easier if you stick with one film and one developer. That's complicated enough. Throwing in other films, other developers, pH changes, dilutions, chemicals, etc. creates a real mess.
K.I.S.S.
Alright, I've done a bunch more experimenting with some mildly interesting, if unsuccessful results. A couple more to come later today, but a question for you all:
I got some pH test strips (obviously not going to be the most accurate things around) so I could play around trying to hit the 9-9.5 level lamerko suggested. The standard H&W Control soup I used looks to be well over that, at around 12, but in testing step-by-step I found that just the distilled-water-sodium-sulfite mix is already at 11. After a quick Googling, it looks like that number should be more like 9. So...what gives?
In my experience the pH of a freshly mixed sodium sulfite solution can initially be as high as ~10 depending on the concentration but will gradually decrease.
That did turn out to be the case! On Friday I mixed up a little batch with two modifications: half the carbonate, and a lower concentration of phenidone as suggested here (the original link is long-dead and the wayback machine is still being a bit wonky after the hack. I did make a pdf copy of it, though) in isopropyl added in at the time of mixing the stock solution.
First, I tried that straight, right after mixing everything. pH of the developer seemed to be around 12. The resulting negs had slightly less fog but were also noticeably thinner than the full-strength ones. The added bonus here was no streaking/swirling! Grain was on par with the other H&W Control tries and accutance/resolution were probably the 'best' I've gotten so far (though that could be down to better focus cameraside). A small crop at approximately 8500dpi:
View attachment 381467
Next, about an hour later, I mixed the same stock solution but added some ascorbic acid bit by bit until the pH seemed to be somewhere in the 9 range. The result was a huge pleasant surprise: no fog! The negs were still very thin, and shadows were blocked up (I might call it a full stop slower than the foggy strip overall), but grain was much finer. Seriously, I had to re-scan because I thought I had maybe missed focus. Accutance was definitely lower, but nothing a bit of USM can't handle. Really promising overall:
View attachment 381465
Then, I tried the final third of the concentrate today, planning on using the 'normal' H&W amount of phenidone but repeating the ascorbic acid thing. However, when I tested the pH, I found it had fallen to around 10, so I left out the acid. Again, no fog! Negs were a bit less thin, too. Speed was maybe 1/2 stop better than the previous test? Grain and accutance about the same (maybe not in this particular sample, but over the entire strip):
View attachment 381466
So, definitely interesting. I'm going to try two more things next: 1. Mixing the full-strength carbonate formula and lowering the pH with the ascorbic acid, and 2. Bumping the carbonate up a bit higher (from half) without the acid to try and find a happy medium between the foggy/streaky negatives and the too-thin ones. The fog isn't that detrimental, anyway, and it has the added benefit of masking the unfortunate spotting phenomenon that results from tiny granules of something or other on the reverse side of the film (threpinner pointed this out to me too). Actually, I think that the best overall result I've gotten so far has been the normal HW recipe but with a prebath in a very dilute sodium carbonate mixture. Still foggy, but no streaking. The only real problem is grain, which I don't really mind anyway.
Yeah, I figured - it's just the only thing I have on hand that would lower the pH (unless I want to start pouring apple cider vinegar into my developer!). Here's an extremely stupid question I have after reading through Anchell and Troop a bit: Is the entire point of the carbonate to raise the pH and make the phen/HQ more active? In that case, wouldn't using the original amount and then forcibly lowering the pH through whatever method be completely redundant? If so, it seems like the mild speed-boosting qualities of H&W Control are directly tied to the fog/grain tradeoff.
Meanwhile, just for fun - it looks like we've finally outresolved the 42mp sensor:
View attachment 381523
Yes, the carbonate is there to set and stabilize the pH. The pH is of H&W control is relatively high to keep developing times reasonable as the working solution is quite dilute. This is one way of formulating a developer of this type but not the only way. You could certainly try lower pH targets using different alkali compounds - or you could also add sodium bicarbonate to create a buffer with a pH closer to say 9.5. Higher alkalinity in and of itself is not what determines emulsion speed.
Another alternative to reduce high fog (typical of relatively alkaline special purpose low contrast Phenidone developers) would be to add small amounts of KBr until you observe a speed loss.
One thing to keep in mind is that the performance of a special purpose low contrast developer is often optimized for a specific film so the results can be quite variable.
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