adan Posted August 17, 2019 Share #1 Posted August 17, 2019 (edited) Advertisement (gone after registration) Brief background: I'm strongly considering switching from HC-110 to a hydroquinone/phenidone developer (Kodak TMax or Ilford DD-X) for fuller film-speed/shadow-detail. In comparing the two (which - BTW - are not exactly the same), I note DD-X contains borax derivatives (tetraborate, boric acid) as alkalizing agents. But I cannot for the life of me figure out which TMax ingredient(s) sets the pH (8.3-8.8) for that developer. It is my understanding that developer solutions generally need to be slightly alkaline to provide the best environment for the development process (reduction of silver halide to metallic silver). Here's the Kodak ingredient list - which (if any) of these would tend to make the solution alkaline? Diethanolamine Sulphur dioxide Sodium bisulphite (Hydroquinone, Phenidone (as 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidinone) Edited August 17, 2019 by adan Quote Link to post Share on other sites More sharing options...
Advertisement Posted August 17, 2019 Posted August 17, 2019 Hi adan, Take a look here Any chemists out there?. I'm sure you'll find what you were looking for!
Jeff S Posted August 17, 2019 Share #2 Posted August 17, 2019 (edited) 33 minutes ago, adan said: Brief background: I'm strongly considering switching from HC-110 to a hydroquinone/phenidone developer (Kodak TMax or Ilford DD-X) for fuller film-speed/shadow-detail. In comparing the two (which - BTW - are not exactly the same), I note DD-X contains borax derivatives (tetraborate, boric acid) as alkalizing agents. But I cannot for the life of me figure out which TMax ingredient(s) sets the pH (8.3-8.8) for that developer. It is my understanding that developer solutions generally need to be slightly alkaline to provide the best environment for the development process (reduction of silver halide to metallic silver). Here's the Kodak ingredient list - which (if any) of these would tend to make the solution alkaline? Diethanolamine Sulphur dioxide Sodium bisulphite (Hydroquinone, Phenidone (as 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidinone) From a brief search, I think Diethanolamine might provide the alkaline base. But I’m no chemist. One of several quotes found... “...Looking at the MSDS information, it appears that the activator is a self-buffered organic alkali, (Diethanolamine- SO2 compound)...” Jeff Edited August 17, 2019 by Jeff S 1 Quote Link to post Share on other sites More sharing options...
AndreasG Posted August 17, 2019 Share #3 Posted August 17, 2019 vor 32 Minuten schrieb Jeff S: From a brief search, I think Diethanolamine might provide the alkaline base. But I’m no chemist. That is correct ( I'm a chemist). 1 1 Quote Link to post Share on other sites More sharing options...
adan Posted August 17, 2019 Author Share #4 Posted August 17, 2019 Interestingly, Ilford's analogous molecule in DD-X is diethylene glycol (a.k.a. 2,2'-Oxybisethanol) - identical structure, but with with an O instead of an NH in the center. As an aside, I was interested in how roughly similar all the "standard" developing agents are - mostly flavors of phenols - given how many partisans each has. Hydroquinone, metol/elon, p-aminophenol (Rodinal), phenidone. Just goes to show how much difference a silly little radical here or there can make. "Poor Henry was a chemist's son; now Henry is no more. For what he drank as H2O was H2SO4." A ditty taught to me at the age of 6 by my father. Thanks, people! 1 Quote Link to post Share on other sites More sharing options...
Martin B Posted September 24, 2019 Share #5 Posted September 24, 2019 Came late to the party, but chemist also. Yes, the amine is a weak Bronsted H+ (proton) acceptor, so it leads to a bit of basic solution. 1 1 Quote Link to post Share on other sites More sharing options...
fotomas Posted September 24, 2019 Share #6 Posted September 24, 2019 Guess the diethylene glycol is mostly to get this stuff so concentrated. But I'm not a chemist. Only mix up my stuff on my own.:-) Quote Link to post Share on other sites More sharing options...
denton Posted March 3, 2023 Share #7 Posted March 3, 2023 Advertisement (gone after registration) Diethyleneglycol is not alkaline, just co solvent. Quote Link to post Share on other sites More sharing options...
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