Everyone should review chemistry for fun! :-)(posted 8178 days ago)Patrick, I never said anything about pH of ascorbic acid. Indeed, the pH depends on the concentration. pKa is simply a negative log of the dissociation constant, and is independent of concentration. There are a lot of misconceptions about what acids are strong and what acids are weak. Without an intention to fix the misconception, I simply state some examples. Citric acid is strong in the sense its pKa and the pH are very small (pH at a typical concentration) and most many of which will release proton when dissolved in water. Yet we can drink it in fruit juice with no harm. Ascorbic acid is weaker than that. Boric acid is much weaker, but you shouldn't drink any appreciable amount.
Tongue tip is very insensitive to bitterness. Although there are classic and recent data that are somewhat controversial to see together, if you stimulate only the tongue tip with some solution, it is a good receptor for sourness but not for bitterness. This tells us that even if it doesn't taste bitter, it does not mean you overdosed bicarbonate. There can be excess bicarbonate without giving you bitter sensation if you only stimulated the anterior portion of the tongue. (You can ask a neuroscientist, coffee cupper, or wine taster :-)
The fact you stated - two moles of NaOH neutralize one mole of carbonic acid is because NaOH is a strong acid and 100% dissociated, and the solubility of CO2(g) only increases as the pH increases. This does not extend to other cases we are talking about.
The developing ability of each developing agent must be evaluated at the targeted pH. It's not just because the concentration of free OH- changes, but also because dissociation of those developing agents change with pH.
Regarding Vitamin C developers developed by Gainer, I think ones that are most useful are phenidone version adjusted for moderate pH, especially if supplemented with a small bit of bromide. Metol versions would benefit from presence of some sulfite (10-60g/liter).
There have been a few additives proposed for Rodinal users. I think some of their effects are due to lowered pH, but this is hard to prove because once you fix the pH of Rodinal it is very different from Rodinal. Ascorbates are likely very different because it is capable of regenerating oxidised developing agents (without silver halide solvent effect) but then one might ask what if I mix my ROdinal with extra p-aminophenol hydrochloride adjusted for suitable pH?
I agree with what Gainer's vitamin C formula try to exploit: because the immediate oxidation product of vitamin C (DHA) is colorless, one might not need sulfite, if ascorbate is abundant and the solution is mixed immediately before use. It somewhat helps cost and environment in some way. I'm not a big fan of Rodinal (doesn't mean I don't like it -- I like something else better) and I like straight Vitamin C formulae better.
However, cheap and good can be bad, like the wine I found last week -- I've been drinking too much just because it's too good and cheap. Hope you figured from my redundant writing and grammatical errors :-)