EDIT: As of right now I've pretty much abandoned PCB and RCB developers for everyday work. There's nothing wrong with them, they work fine and I have no issues, but I found that I can achieve the same results of both PCB and RCB with PCM. Just trying to simplify things for myself.
What are your "go to" developers?
MM
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My go-to developers are an old bottle of Agfa Rodinal that seems to last forever and just a quick mix of Kafenol 327 which is nothing more than Reinhold's CC-M, I use a teaspoon measure and measures out 3 - 2 and 7 measures in quick succession, for one tank of 35mm film. The developer seems to tackle most films, and I use it for all types of films (even KOdachrome) if necessary.
In earlier times D76, and Accufine was my go-to developers, these days I have to travel to find that....
EP
Think I'm getting confused here : PCB... is that the same as the recipe outlined in "Tylenol and ascporbate : it works?" and which was named TCB at the time? I was wondering if it was possible to do that one in a little simpler way??
ReplyDeletePCB is the recipe I mentioned in my initial e-mail ... it's the re-usable Phenidone/Vit-C/Borax developer. I did more experimenting with TCB trying to simplify it but did not have much success. I found that filtering the binder from the tablets reduced activity, I'm not sure if it's oxidation from the filtering process or that p-Aminophenol gets filtered out as well. Practically, it all settles to the bottom anyway so the extra "bits" are of no consequence. I also tried eliminating the ascorbate conversion with bicarbonate but this did not work well. I tried adding enough additional hydroxide to neutralize the ascorbate, which worked, but found that the tablets did not dissolve well in the higher pH solution. This would probably be okay if using acetaminophen powder but using tablets needs lower pH. A combination that I have not tried that might work just as well is to add the ascorbic acid, dissolve the tylenol, then add the hydroxide. My only concern is I don't know if ascorbic acid has the same preservative properties as sodium ascorbate which would let the acetaminophen oxidize. I'm also assuming that the acetaminophen needs a preservative which it may not, I'm not sure. It may be possible to prepare TCB by simply dissolving acetaminophen tablets in water, adding ascorbic acid, then adding sodium hydroxide. These are things I need to try.
ReplyDeleteI just did a quick experiment and have some interesting results. I used 250mL water with 4g ascorbic acid and 30 acetaminophen tablets. I agitated the container a bit then let it sit for 20 mins and found that the tablets were nearly dissolved. This makes sense as the tablets are meant to be dissolved in an acid environment. I will try adding the hydroxide when completely dissolved, let the p-aminophenol conversion take place, then try the developer. I might try metaborate this time as it's still a very good buffer with higher pH than borax so it should be a bit more active.
ReplyDeleteI added the hydroxide and let it sit. I do notice something different in that practically everything is dissolved. Remember that I did not crush or filter the tablets, I just let them dissolve in ascorbic acid solution. What's particularly interesting is that all the other "stuff" usually settles to the bottom in a few hours but with this brew there's hardly anything on the bottom with small particles suspended in solution. I have also altered the formula slightly to more closely resemble parodinal as follows:
ReplyDeleteWater - 250mL
Ascorbic Acid - 4g
Acetaminophen - 15g
Once tablets are dissolved I added 20g sodium hydroxide. This is very similar to Parodinal with ascorbic acid instead of sulfite. After 72 hours I will add 25g borax, 9g ascorbic acid, and water to make 1L. This will be part A that will be diluted with a part B (borax @ 19g/L + ascorbic acid @ 6g/L) for a working strength solution.
Previous experiments showed that this worked but I needed much more of part A compared to using parodinal. I think that the issue may be not enough p-aminophenol being created by the dissolving process so I'm hoping this new method will address that. I'll test in a few days once the developer has ripened.