Any chemists out there?

[adan]

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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

[Jeff S]

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

[AndreasG]

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).

[adan]

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!

[Martin B]

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. 

[fotomas]

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.:-)

[denton]

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Diethyleneglycol is not alkaline, just co solvent.