replenishment for pppd?

[phritz phantom]

first, thanks to donald for that wonderful formula. this just became my favourite developer. i used an catechol-only version, since i can't get any pyro right now. at first i wanted to use it as the soft developer in a two-bath process (since it's catechol only, i expected it to be very warm and soft in tone), but, surprisingly, this is very contrasty.
this is the formula i used: 15g sulfite, 0,2gr phenidone, 7,5gr catechol, 46,6gr crystal soda, 0,2gr pot. bromide.
for 500ml
(i overread the citric acid in the updated version)

so, this is a rather potent formula (the image emergence time is just a few seconds, like 5ish) and catechol is rather costly for me, is there a way of replenishing the developer? like adding more carbonate?

and how would adding the missing pyrogallol and/or the citric acid affect the resulting image tone?

thanks.

 

[gainer]

You could try hydroquinone in place of catechol. It also is a staining developer, but with more reddish hue to my eye, and is cheaper. Hydroquinone and catechol are both dihydroxybenzene but one of the hydroxys is in a different place on the ring. Pyrogallol is a trihdroxybenzene.

 

[phritz phantom]

hmm thanks
i don't think i'd want to completely get rid of the catechol (maybe a half/half hydroquinone/catechol), but donald miller mentioned on the unblinkingeye hp, that it doesn't keep well. the formula seems to be very potent (at least i think, because of the fast image emergence time), so it will rather die of deterioration, oxidation,... than exhaustion of the developing agent.
maybe if it could be used until exhausted, it would be a very economical developer.
today will be the third day of printing with the batch i made, on the second day i didn't notice any signs of deterioration.

 

[Donald Miller]

phritz,

I believe the Pyro makes it go off much more rapidly. Lee Carmichael has mentioned that he gets decent life out of it as well. You might try replenishment by adding back at the first sign of longer emergence times.

You might try adding back 30% of the original amounts and see what affect it will have in extending life

I have not used the developer since I bought five pounds of Amidol awhile back.

 

[phritz phantom]

thanks for your reply, donald.
on my third day of printing (about 20-25 sheets of 24x30cm paper althogether) and it still works fine, even though there's only 250ml left.

now i tried something else, i brewed a mixture of catechol, phenidone and hydroquinone.
for 500ml: 15gr sodium sulfite, 0,2gr phenidone, 5gr catechol, 7gr hydroquinone, 50gr crystal soda and 0,4 pot. bromide
i used it in a 1+1 working solution with 20ml of a 0,1% solution of benzotriazole.
it gave me results quite alike the catechol-only pppd. although a bit less warm (less brown tone). the image emergence time is around 30s, but nevertheless i had to reduce exposure by a third to get the same results as with the pppd.

any thoughts/ improvenments for my formula?

thanks.