Friday, April 1, 2011

PCC - Phenidone/Vitamin-C/Carbonate (No Borax)

Here is a variant we'll call PCC based on work from Patrick Gainer that uses sodium carbonate in place of borax:

Sodium Carbonate - 7g
Ascorbic Acid - 6g
Phenidone - 0.15g
Water to make 1L

This is quite active so I thought it might be good for C-41 films that generally need a little extra "kick" when processed as black-and-white.  Here is a frame from long expired Fuji Superia 400 @ EI400 developed for 8mins with normal agitation:

Processed as normal for me with no adjustments except re-size and JPEG conversion.

This should work for at least 12 rolls.  My concern is buffer capacity of the sodium carbonate (this is another reason I like borax ... it's a really good buffer) so I'm thinking a bicarbonate/carbonate buffer may work better than straight carbonate and can be adjusted to bring the pH down to that of borax.  I should be able to make this work with acetaminophen as well which uses tylenol + sodium hydroxide to make p-aminophenol instead of phenidone.



  1. I'll do theoretical calculations for you - pH, just tell me what you want!

    I'll do this recipe for now, if I had phenidone on hand I'd mneasure it as well, I have a calibrated pH measure.... (teorie und praxis sind NICHT gleich!)

    I will follow this closely sodium bicarbonate is an excellent proposition! <I'll give that a spin in the calculator.

  2. pH of borax ends up at 9.2 so I think somewhere close to that would be good.

  3. ph of 7 g Soda alone :

    7g Na2 CO3 = 0,066M ph 11,56

  4. 7 g Sodium bicarbonate = 0,083M

    A mix between 7 g of soda and 7 g bicarbonate should have a pH around 10.2.... this is a complex solution to calculate... I would NOT have done it with a slide rule!

  5. A mix of 5 g soda and 14 g bicarbonate should be around pH9,8

    I think I would start with 7-7 since the other stuff DO adjust pH also ionic activity was mentioned.

  6. You think its necessary to use NaOH (Lye) to kick the tylenol(acetaminophen) over to p-aminophenol? This will not happen with soda alone? NaOh - even a small amount would skyrocket pH to 12, even as little as 0,4 gram...

  7. 7 g soda, 7 g bicarbonate 6 g ascorbic acid :

    ph 9,75

    you have twice the molarity of soda vs ascorbic acid : soda in excess.... but how much NaOH is needed for the tylenol?

  8. Thanks for the info on the carbonate/bicarbonate buffer ... I will try it. This is similar to the conclusion I came to using tables I found online. I'm not certain about the p-aminophenol conversion but I know it does work with sodium hydroxide but am willing to try with soda. Based on my notes 1g acetaminophen + 0.265g sodium hydroxide makes 0.722g p-aminophenol + sodium acetate. I don't know how to calculate how much soda would be required instead.

  9. 0,265 gram NaOH = 0.006625 mol

    0,006625 mol Na2CO3 (soda) = 0,70225 gram

    You can covert from here... i.e. for this purpose and in this context replace 1 gram NaOH with 2,65 gram washing soda... havent given that a thought as to pH but since soda is a weaker alkali, you probably needs more than that to keep up the pH.