Home made D76 with raw chemistry?

[hadeer]

The metol will not dissolve in the sulfite solution. There's special magic in the Kodak manufacturing process that makes it work.

Hi Brad,
I have followed that discussion, and I was under the impression that this "Kodak magic" just served to prevent the cross contamination of the materials during storage and transport. Maybe I'm wrong though.
Hans

 

[BradS]

Hi Brad,
I have followed that discussion, and I was under the impression that this "Kodak magic" just served to prevent the cross contamination of the materials during storage and transport. Maybe I'm wrong though.
Hans

Try it and let us know what you find.

 

[Ian Grant]

I never do and to my opinion it makes no difference. I make my D-76H (Grant Haist formula, no hydroquinone) from raw chemicals, most of the time just enough to make developer for the film at hand, directly in a 1:1 solution and use it right away. Worst problem: cool it down sufficiently fast. I get consistent results after initial testing with 2-3 films with good tonescale and density on Tmax 400 as well as Tmax 100.
I wonder if one could dissolve all the chemicals in one batch instead of adding them one by one. Never tried. Anyone? Seems to be the case with the commercial available D-76 from Kodak.
Hans

I've done both and it made no difference either, in a variety of formulae.

I've also put all the dry chemistry together and mixed, ala Kodak, again no difference.

But I normally mix in the order specified.

Ian

 

[dancqu]

Metol in solution is acidic and is not likely to oxidize
any more than it already has.

The earliest instructions I have seen, in Hardy & Perrin
"Principles of Optics", 1930, say to dissolve the Metol
in a small amount of water,

"... not likely to oxidize" is not the same as "will not oxidize"
Dissolved oxygen is elemental. Elemental uncombined oxygen
is a very strong oxidizer.

"... dissolve the Metol in a small amount of water ..."
Little water little dissolved oxygen. Dan

 

[gainer]

"... not likely to oxidize" is not the same as "will not oxidize"
Dissolved oxygen is elemental. Elemental uncombined oxygen
is a very strong oxidizer.

"... dissolve the Metol in a small amount of water ..."
Little water little dissolved oxygen. Dan

Does not the pH have an effect? Dissolved oxygen should tend toward basic, depending on what else is in there. I don't know about aerial oxidation, but Metol won't do much developing at pH less than 5, which is what I measured when I dissolved 2 grams in 100 ml water.

My theory as to why the earliest instructions were to dissolve the metol first in water seemed to make sense, as I have seen elsewhere that sulfite does not regenerate Metol but prevents the oxidized Metol from restraining development. OTH. hydroquinone+ sulfite does regenerate Metol as part, at least, of superadditivity, as does ascorbate without sulfite. That is why I would prefer to see the Metol added after the hydroquinone and sulfite. We know that Metol doesn't want to dissolve under those conditions, So we dissolve it first with a "pinch" of sulfite. OK then, why not a pinch of hydroquinone AND a pinch of sulfite, or maybe just a pinch of ascorbic acid?

 

[Nicholas Lindan]

I add a pinch of S. Sulfite before the metol. I was under the impression the sulfite scavenges the dissolved oxygen from the water to minimize the oxidation of the metol when it is added to the solution.

As to Kodak's 'magic' of dumping all the ingredients into the pot at once - I find it a PITA: the water has to be really hot and you have to stir for a very long time for the last crystals to disappear. As I make developer stock from distilled water it means I have to heat the water to the right temperature in the kitchen and then take it to the darkroom. If the D76 is made from scratch everything dissolves in seconds and it can be made up with room temperature water. I would prefer a two package formulation from Kodak, I think the single packet idea is to save Kodak money, and not to make my life any easier (though I guess if it saves Kodak money, it also saves me money).

 

[Kirk Keyes]

Does not the pH have an effect? Dissolved oxygen should tend toward basic, depending on what else is in there.

No, it does not. Dissolved oxygen has no effect on pH. The oxygen is dissolved O2, and it is does not form OH- ion as you seem to think.

 

[Kirk Keyes]

Dissolved oxygen is elemental. Elemental uncombined oxygen
is a very strong oxidizer.

Again, wrong. It is not "elemental". Dissolved oxygen is molecular oxygen, O2. That said, it is still an oxidizer. You will not find elemental oxygen around in nature, as it will react with another oxygen and from ozone. Look at electrolysis, you've just broken apart a water molecule, and the "elemental" oxygen rapidly forms diatomic, molecular oxygen.

(At very high temperatures, like >5000K, you can get dissociation of molecular oxygen, but not at any temps we are interested in.)

When air dissolves in water, the oxygen does not ionize. It simply dissolves. Same with nitrogen. They are both diatomic molecules and they do not ionize in water.

Think about it, guys. If oxygen did "decompose" and raise the pH of water, all of our oceans, rivers, and other natural bodies of water would eventually become caustic and nothing could live in them...

 

[hadeer]

....If the D76 is made from scratch everything dissolves in seconds and it can be made up with room temperature water........

Nicholas,
Thanks for this tip, I certainly am going to try it the next time I prepare a shot of D-76H. As I said before, it always stretches your patience to wait for the temperature to come down after mixing. Silly though that I never even thought of trying to use room temperature water.... So powerfull is a habit once it is formed.
Hans

 

[Keith Tapscott.]

I add a pinch of S. Sulfite before the metol.

If the D76 is made from scratch everything dissolves in seconds and it can be made up with room temperature water.

I would prefer a two package formulation from Kodak, I think the single packet idea is to save Kodak money, and not to make my life any easier (though I guess if it saves Kodak money, it also saves me money).

I am guessing that D-76 is cheaper than ID-11 in you location.
I also make my own D-76 (ID-11) to the ORIGINAL formula by starting with a `pinch` of the weighed sulphite. I make up the required volume of stock which I allow to settle for a day or two and always use it well with in a week of mixing.
It`s simple to make and satisfies most of my requirements. I like it diluted 1+1 (one-shot).

 

[dancqu]

Does not the pH have an effect?

Very likely Metol is safer at a low ph as generally
materials which can be oxidized are less prone to
do so in an acidic environment.

But who knows for sure. Metol may be oxidized by
free oxygen even at a low ph of 3.6; the ph I've
read when testing a 0.3% solution.

A pinch of bisulfite might make more since.
It has been recommended for the preservation
of solutions of phenidone. Dan

 

[dancqu]

[QUOTES=Kirk Keyes;869791]
"It is not "elemental". Dissolved oxygen is molecular
oxygen, O2. That said, it is still an oxidizer."

Elemental in the sense of the oxygen in the water being
uncombined, free.

"Think about it, guys. If oxygen did "decompose" and raise
the pH of water, all of our oceans, rivers, and other natural
bodies of water would eventually become caustic and nothing
could live in them..."

As it is the oceans are becoming acidic. Crustaceans are
beginning to effervesce. Dan

 

[gainer]

Again, wrong. It is not "elemental". Dissolved oxygen is molecular oxygen, O2. That said, it is still an oxidizer. You will not find elemental oxygen around in nature, as it will react with another oxygen and from ozone. Look at electrolysis, you've just broken apart a water molecule, and the "elemental" oxygen rapidly forms diatomic, molecular oxygen.

(At very high temperatures, like >5000K, you can get dissociation of molecular oxygen, but not at any temps we are interested in.)

When air dissolves in water, the oxygen does not ionize. It simply dissolves. Same with nitrogen. They are both diatomic molecules and they do not ionize in water.

Think about it, guys. If oxygen did "decompose" and raise the pH of water, all of our oceans, rivers, and other natural bodies of water would eventually become caustic and nothing could live in them...

My original post had nothing much to do with what the water would do to the Metol, dissolved air or not. It concerned the initial state of the Metol, which could be already partially oxidized. Sulfite does not, from what I have read in "The Theory of the Photographic Process", regenerate the Metol, but changes the oxidized portion to a form that does not inhibit development. If all the Metol were oxidized, it would be converted to a compound tht does not inhibit development, but there would be no development either. Ascorbic acid OTH was said to actually regenerate the Metol. This fact shows as if it were superadditivity in some cases. It is difficult or impossible to tell by performance whether a developer is a simple combination of Metol and ascorbate or a combination of Metol, hydroquinone and sulfite. Over the short term, Metol and sulfite is in that group, Metol and hydroquinone without sulfite are no better than Metol alone.

In this kind of group, you can leave out the pejorative expression like "as you seem to thiink."

 

[BradS]

....Metol and hydroquinone without sulfite are no better than Metol alone.

Mr. Gainer,
You may find section 25-5 of the following interesting....
John D. Roberts and Marjorie C. Caserio
Basic Priciples of Organic Chemistry
(C) 1964, W.A. Benjamin, Inc.

Library of congress cat no. 64-16071

specifically:

Sodium sulfite has a preservative action on alkaline developer solutions and also acts to convert the quinone formed in the developing process by a 1,4-addition to hydroquinone-sulfonic acid.

The sulfonic acid has itself some developing power and, in the presence of sulfite, more than one equivalent of silver bromide can be produced for each equivalent of hydroquinone used in making up the developer.

 

[dynachrome]

The way to get a magnetic mixer to work in a satsifactory way is to use a container with a flat bottom. As long as the speed is set properly the mixer can make it easier to prepare developers from powder. My magnetic mixer came from a camera store which was closing and cost very little. The teflon coated magnets I had to buy separately cost more than the mixer.

 

[gainer]

Mr. Gainer,
You may find section 25-5 of the following interesting....
John D. Roberts and Marjorie C. Caserio
Basic Priciples of Organic Chemistry
(C) 1964, W.A. Benjamin, Inc.

Library of congress cat no. 64-16071

specifically:

Thanks for the lead. Lest anyone get the wrong idea, I am not suggesting leaving out the sulfite, but am only arguing that there may be a valid reason for not adding it without first mixing with it some hydroquinone, as is specified in "The Principles of Optics" by Hardy and Perrin. They do not explain why it is to be done this way, nor do they call the developer D-76, but it can be no other, and they do say it is recommended by Eastman Kodak for producing fine grain. The book was in its first edition, third impression in 1932. I do know from more recent work that sulfite works to convert oxidized Metol to a sulfonate, while ascorbate acts to regenerate it back to Metol. Hydroquinone without sulfite does neither. Hydroquinone with sulfite regenerates Metol.

Nutshell: oxidized metol + sulfite => sulfonate. Oxidized Metol + ascorbic acid => regenerated Metol. Oxidized Metol + hydroquinone + sulfite => regenerated Metol. My opinion is that if you want to add a pinch of anything with the Metol, it should be ascorbic acid. It will keep the solution acidic and is a strong antioxidant. It is known to regenerate oxidized Metol, and in fact can substitute for both sulfite and hydroquinone at the same time. Look at www.unblinkingeye.com for Vitamin C developers.

 

[Kirk Keyes]

In this kind of group, you can leave out the pejorative expression like "as you seem to thiink."

No perjorative intended.

I was addressing what appeared to me to be your belief that dissolved oxygen would have an effect on pH.

Maybe you can clarify your statement then.

Dissolved oxygen should tend toward basic, depending on what else is in there.

 

[dancqu]

Mr. Gainer, You may find section 25-5 of the following
interesting....John D. Roberts and Marjorie C. Caserio
Basic Priciples of Organic Chemistry
(C) 1964, W.A. Benjamin, Inc.

I find it interesting. Do they go on to describe the
action of the quinone in the absence of sulfite;
an exponential increase in hydroquinone
sulfonic acid? Dan

 

[BradS]

I find it interesting. Do they go on to describe the action of the quinone in the absence of sulfite; an exponential increase in hydroquinone sulfonic acid? Dan

No, This section comes in the middle of a chapter on phenols and quinones. Section 25-5 is short and sweet and focuses on how hydroquinone works as a B&W film developer. It si one of those "see this stuff really does have some real-world application" sections. They go on to show how the commonly used developing agents, Metol, Hydroquinone, (the active agent in) Rodinal, and Amidol are structurally similar.

 

[Photo Engineer]

Mr. Gainer,
You may find section 25-5 of the following interesting....
John D. Roberts and Marjorie C. Caserio
Basic Priciples of Organic Chemistry
(C) 1964, W.A. Benjamin, Inc.

Library of congress cat no. 64-16071

specifically:

This, of course, is specifically outlined in detail by Mees and James and by Haist. They go on to point out that hydroxide ion is produced in this reaction and that the pH "wobbles" for the first few hours after mixing due to consumption of Oxygen, and production of HQMS. Therefore, the activity of any HQ based developer also "wobbles" for the first few hours after mixing. The developer thus is designed to minimize these "wobulations".

PE

 

[gainer]

No perjorative intended.

I was addressing what appeared to me to be your belief that dissolved oxygen would have an effect on pH.

Maybe you can clarify your statement then.

Nope. I should have left it as a question: "Does the pH have an effect?". It was either too late at night or too early in the morning. Those times are often simultaneous for me.

 

[dancqu]

No, This section comes in the middle of a chapter on phenols
and quinones. Section 25-5 is short and sweet and focuses
on how hydroquinone works as a B&W film developer.

I thought they might go on to explain the occurrence
of lith development in the absence of sulfite.

As I understand the matter, the quinone produced upon
hydroquinone's reduction of the silver halides will oxidize
two hydroquinone producing two semi-quinone,
hydroquinone-sulfonic acid.

The semi-quinone is an active developing agent so becoming
quinone. An exponential increase in semi-quinone occurs.
The result, a lith developer.

A basic lith developer is very simple; nothing more than
hydroquinone, a very little sodium sulfite, and
some Sodium carbonate. Dan

 

[gainer]

As a matter of interest, I have copied the instructions as follows.

 

[gainer]

Another point of interest is the high mixing temperature, even while the Metol is in water alone. It may in fact be true that heating the water removes at least as much of the dissolved oxygen as the "pinch" of sulfite. The solubility of oxygen in water is approximately half at 71 C that it is at 20 C. Maybe we should use both belt and suspenders and heat the water as well as use the pinch of sulfite or ascorbate.

 

[Anscojohn]

Another point of interest is the high mixing temperature, even while the Metol is in water alone. It may in fact be true that heating the water removes at least as much of the dissolved oxygen as the "pinch" of sulfite. The solubility of oxygen in water is approximately half at 71 C that it is at 20 C. Maybe we should use both belt and suspenders and heat the water as well as use the pinch of sulfite or ascorbate.

*******
I was taught to mix developer starting at 125 F. And to add the "pinch." I was also taught to let the final product sit 24 hours before using it. That is what I still do.