Diluted D-76 & Imporved D-76 at dilution

"Lew" wrote in message
...
Is it possible that my home brewed, 'improved,' no
hydroquinone D-76
would be less active at 1:3 dilution than standard, out of
the box
D-76? Although my home made D-76 compares favorably with
store bought
D-76, results at 1:3 seem underdeveloped.

It could be. The amount of metol in standard D-76 is
minimal. I would suggest increasing it to perhaps 5 grams
per liter.
Also, in general, the activity of the developer is
slightly lower than standard D-76. This is shown in the
graphs in the 1929 paper from Kodak Research Labs. Metol and
hydroquinone act to regenerate each other but in D-76 the pH
is too low to activate hydroquinone as an effective
developer. So, the developer works about the same without
the hydroquinone but has a shorter life and there may be
differences in such things as edge/border effects (less with
the hydroquinone present).



--
Richard Knoppow
Los Angeles, CA, USA

"Lew" wrote in message
...
Is it possible that my home brewed, 'improved,' no
hydroquinone D-76
would be less active at 1:3 dilution than standard, out of
the box
D-76? Although my home made D-76 compares favorably with
store bought
D-76, results at 1:3 seem underdeveloped.

The Borax in D-76 is there as a buffering agent. If you leave out the Hydroquinone, then you might as well leave out the Borax as well, as it is only mildly alkaline.
The neatest answer is to use Metol and Sulphite alone, as in Hans Windisch`s Metol, Sulphite compensating formula and Kodak D-23.

"Keith Tapscott."
wrote in message
...

"Lew" wrote in message
...-
Is it possible that my home brewed, 'improved,' no
hydroquinone D-76
would be less active at 1:3 dilution than standard, out
of
the box
D-76? Although my home made D-76 compares favorably with
store bought
D-76, results at 1:3 seem underdeveloped.-The Borax in
D-76 is there as a buffering agent. If you leave out the
Hydroquinone, then you might as well leave out the Borax
as well, as it
is only mildly alkaline.
The neatest answer is to use Metol and Sulphite alone, as
in Hans
Windisch`s Metol, Sulphite compensating formula and Kodak
D-23.




--
Keith Tapscott.

The borax is not a buffering agent, it is an alkali for
the purpose of electrolyzing the developing agents and is
significantly higher in pH than sulfite alone. D-76d, a
Kodak formula is buffered by using a combination of borax
and boric acid to maintain a constant pH but it is the same
as the pH of freshly mixed regular D-76.
The pH of borax is not high enough to activate the
hydroquinone in D-76. Without the metol the solution will
barely develop at all. However, the hydroquinone still
interacts with the metol. The two act to mutually preserve
and regenerate each other so that D-76 has a larger capacity
than a similar developer without the hydroquinone.
Metol will develop quite nicely without the
hydroquinone, however, formulas with only metol in them
usually contain a considerably larger quantity of metol than
D-76 in order to have a reasonably high capacity. There were
numerous "fine grain" developers during the 1940s using
metol and carbonate. However, metol will develop even in a
slightly acid soluton so it can be used with sulfite along
as the alkali, as in D-23, or in sulfite buffered to neutral
with metabisulfite, as in D-25. both formulas have 7.5
grams/liter of metol in contrast to the 2 grams in D-76.
Kodak has never recommended D-76 at 1:3, however,
Ilford gives times for ID-11 for this dilution. They are
about right for D-76 also. At 1:3 either developer becomes a
high acutance develope with exagerated edge/border effects
and some compensation (shouldering off at high densities).
I've used it but don't much like the way it looks.
Low contrast is usually from insufficient development
time. At 1:3 D-76 will require at least double the time
given for it full strength and maybe more.
Kodak D-23 gives approximately the same grain and speed
as D-76 but with somewhat longer development times. It is
about the simplest developer formula possible:

Kodak D-23
Water (at about 125F or 52C) 750.0 ml
Metol 7.5 grams
Sodium sulfite, desiccated 100.0 grams
Water to make 1.0 liter

Here is Windisch's version as a compensating developer,
probably the one you mean:

Water 1.0 liter
Sodium sulfite 100.0 grams
Metol 2.5 grams



Windisch proposed several developers. One well known one
uses orthophenylenediamine as a silver solvent.
Orthophenylenediamine is related to paraphenylenediamine, a
popular extra-fine-grain developer popular in the 1930s and
1940s but it has no developing activity.
Paraphenylenediamine was thought to produce extra fine grain
due to its considerable halide solvent properties. It did
this at a very considerable loss of speed and a need for
very long development times to achieve any degree of
contrast. It was usually used on combination with Glycin.
Windisch's idea was to combine the inactive form of the
developer with metol to obtain a very fine grain developer
which still delivered reasonable film speed. The formula for
this follows:
Windisch fine grain developer
Water (boiled) 600.0 ml
Sodium sulfite 55.0 grams
Orthophenylenediamine 7.0 grams
Metol 7.0 grams
Potassium metabisulfite 6,0 grams
Water to make 1.0 ml

Dissolve all the chemicals except the sulfite after the
water has cooled to lukewarm. When fully dissolved add the
sulfite and bisulfite.
Speed loss is about one stop.
The form of the sulfite is not specified but is probably
desiccated.
I have no idea if this is a practical formula.
A compensating developer attributed to Windisch follows:

Solution A
Water 100.0 ml
Pyrocatechin 8.0 grams
Sodium sulfite 1.25 grams

Soluton B
10 per. cent. solution of sodium hydroxide.
For normal use take 12 parts of A and 7 parts of B to 500
parts of water. He gives some other variations.

D-76 and D-23 do not need anti-foggants as would a
developer with carbonate. However, fresh D-76 (and probably
D-23) will deliver very slightly higher film speed if about
0.25 grams/liter of potassium bromide is added to the stock
solution. This suppresses a slight tendency to fog
characteristic of D-76 type developers. Where the developer
is re-used or used in a replenished system the bromide from
the film will accomplish the same thing.

For reference and comparison here is a typical fine
grain carbonate type developer of the same period:

Agfa-12 Fine Grain Tank Developer
Water (at 125F or 52C) 750.0 ml
Metol 8.0 grams
Sodium sulfite, desiccated 125.0 grams
Sodium carbonate, monohydrated 5.75 grams
Potassium bromide 2.5 grams
Water to make 1.0 liter



--
Richard Knoppow
Los Angeles, CA, USA

Originally Posted by Richard Knoppow

The borax is not a buffering agent, it is an alkali for
the purpose of electrolyzing the developing agents and is
significantly higher in pH than sulfite alone.

The pH of borax is not high enough to activate the
hydroquinone in D-76.

Kodak D-23 gives approximately the same grain and speed
as D-76 but with somewhat longer development times. It is
about the simplest developer formula possible:

Kodak D-23
Water (at about 125F or 52C) 750.0 ml
Metol 7.5 grams
Sodium sulfite, desiccated 100.0 grams
Water to make 1.0 liter

Here is Windisch's version as a compensating developer,
probably the one you mean:

Water 1.0 liter
Sodium sulfite 100.0 grams
Metol 2.5 grams
--
Richard Knoppow
Los Angeles, CA, USA

The borax in D-76 is indeed a pH buffer.

http://www.borax.com/detergents/pheffect.html

I have never really seen the point of the so called D-76H formula which isn`t an actual Kodak formula by the way, but is acknowledged as a suggested formula by Grant Haist, a former Kodak photo-chemist (hence the `H`).
There is in fact an official Kodak formula called D-76h which is a buffered-borax MQ developer, just to add confusion.

From MODERN PHOTOGRAPHIC PROCESSING (Volume 1) by Grant Haist on page 246.

"THE SULFITE ALKALI`S. "Sodium sulfite is a weakly alkaline salt that is capable of acting as the sole alkali for developing agents of the amino groups, as for example, Metol or Amidol. Sodium sulfite is an alkali because it hydrolyzes in solution to produce sodium hydroxide" (caustic soda).

The borax in D-76 is there to prevent or at least minimise a rise in pH due to the complexes formed by the sulphite to produce hydroxide which can activate the hydroquinone. If the hydroquinone is left out, then you don`t need the borax.

As you have said, Metol-sulphite developers are as simple as it gets, so there is no need to add borax to obtain a very effective fine-grain developer.

The formula I have seen for Windisch Metol-Sulphite developer is 2.5 grams of Metol and 50 grams of sodium sulphite, (crystalline) in a litre of water.

The point I am trying to make is if a D-76 type of developer is required, then keep the Hydroquinone in the formula and add a borate to stabilise the pH, other wise make a D-23 type instead. Sulphite is the only alkali required for the D-23 type of developer, there is no need at all to add borax or Kodalk.

"Keith Tapscott."
wrote in message
...

Richard Knoppow;848014 Wrote:


_The_borax_is_not_a_buffering_agent,_it_is_an_alka li_for_
the_purpose_of_electrolyzing_the_developing_agents _and_is_
significantly_higher_in_pH_than_sulfite_alone._

The pH of borax is not high enough to activate the
hydroquinone in D-76.

Kodak D-23 gives approximately the same grain and speed
as D-76 but with somewhat longer development times. It is
about the simplest developer formula possible:

Kodak D-23
Water (at about 125F or 52C) 750.0 ml
Metol 7.5 grams
Sodium sulfite, desiccated 100.0 grams
Water to make 1.0 liter

Here is Windisch's version as a compensating developer,
probably the one you mean:

Water 1.0 liter
Sodium sulfite 100.0 grams
Metol 2.5 grams
--
Richard Knoppow
Los Angeles, CA, USA
he borax in D-76 is indeed a pH
buffer.

http://www.borax.com/detergents/pheffect.html

I have never really seen the point of the so called D-76H
formula which
isn`t an actual Kodak formula by the way, but is
acknowledged as a
suggested formula by Grant Haist, a former Kodak
photo-chemist (hence
the `H`).
There is in fact an official Kodak formula called D-76h
which is a
buffered-borax MQ developer, just to add confusion.

From MODERN PHOTOGRAPHIC PROCESSING (Volume 1) by Grant
Haist on page
246.

"THE SULFITE ALKALI`S. "Sodium sulfite is a weakly
alkaline salt that
is capable of acting as the sole alkali for developing
agents of the
amino groups, as for example, Metol or Amidol. Sodium
sulfite is an
alkali because it hydrolyzes in solution to produce sodium
hydroxide"
(caustic soda).

The borax in D-76 is there to prevent or at least minimise
a rise in pH
due to the complexes formed by the sulphite to produce
hydroxide which
can activate the hydroquinone. If the hydroquinone is left
out, then
you don`t need the borax.

As you have said, Metol-sulphite developers are as simple
as it gets,
so there is no need to add borax to obtain a very
effective fine-grain
developer.

The formula I have seen for Windisch Metol-Sulphite
developer is 2.5
grams of Metol and 50 grams of sodium sulphite,
(crystalline) in a
litre of water.

The point I am trying to make is if a D-76 type of
developer is
required, then keep the Hydroquinone in the formula and
add a borate to
stabilise the pH, other wise make a D-23 type instead.
Sulphite is the
only alkali required for the D-23 type of developer, there
is no need
at all to add borax or Kodalk.




--
Keith Tapscott.

I don't know where my copy of Haist is. The pH of D-76
is considerably higher than that of D-23 due to the borax.
Borax has some buffer action but is not a good buffer. The
reaction of hydroquinone with sulfite was not known when
D-76 was formulated nor was it discovered for about three
decades after. The rise in pH was observed and a buffer of
borax and boric acid was substituted for the borax only in
the D-76d formula described in Capstaff's 1929 paper.
If the hydroquinone isx not present there is probably no
rise in pH. If the borax is left out the effect will still
take place, as you state, but the activity of the developer
will be less. I think the target pH of D-76 is about 8.7, I
can't remember what it is for D-23. In any case, if the
hydroquinone is left out of D-76 there is little difference
in activity as pointed out in the 1929 paper which explored
something like 30 variations of the formula. The one thing
that they did not try was a metol-sulfite developer. I think
perhaps the films of the time would have required too long a
development time with it or, perhaps, they just didn't think
of it.
The paper was published in the _Transactions of the
Society of Motion Picture Engineers_ the quarterly
predecessor of the Journal. They are hard to find. I have a
copy because a friend with access to the MIT library Xeroxed
it for me. I will find the citation for you because it is a
very interesting paper. I don't think many other developers
were ever analysed as thoroughly as D-76.
There was another variation of D-76 which was published
sometime about the mid 1930 at the time Kodak was pushing
Kodalk (sodium metaborate) as an alkali for all developers.
This one uses Kodalk instead of borax. Supposedly it Kodalk
had better buffering qualities than borax but it turned out
not to so the formula was never used much. It is identical
to the original D-76 but has 2 grams per liter of Kodalk
instead of borax. I think its possible that Packaged D-76 at
one time contained metaborate but the current stuff is a
variation of the buffered formula.
D-25, pubished about the same time as D-23 (early
1940s) is D-23 buffered to neutral pH with metabisulfite.
The lower activity makes it a very fine grain developer but
I think it had problems with dichroic fog with some films.
The old DK-20 formula, which contained sodium thiocyanate as
a silver halide solvent had serious problems with post-WW-2
emulsions and was discontinued as a packaged product. It is
an interesting formula but no longer practical. D-25 is just
as fine grain and works for more films. Microdol-X has a
proprietary formula although there are similar formulas in
some Kodak patents. It uses sodium chloride (common salt) as
the fine grain agent. I think Haist talks about this a
little but doesn't really give a full explanation of how it
works. I think he may have been constrained by being a
former Kodak employee not to disclose stuff Kodak considered
trade-secrets.


--
--
Richard Knoppow
Los Angeles, CA, USA

Originally Posted by Richard Knoppow

"Keith Tapscott."
wrote in message
...

Richard Knoppow;848014 Wrote:

The borax in D-76 is indeed a pH
buffer.
http://www.borax.com/detergents/pheffect.html--
Keith Tapscott.


"Borax has some buffer action but is not a good buffer".

I have to disagree that borax is a poor buffering agent for reasons I have already provided in the link. You seem to be ignoring the complexes formed when sulphite and borax are dissolved in solution. D-76 does only contain 2 grams per litre, but extra borax as in some of the D-76 derivatives such as Ansco/Agfa 17, Adox borax MQ and Kodak`s own D-96 will provide greater buffering capacity.
Borax releases a whole myriad of boron ions when it is dissolved, including B2O3 (boric anhydride). It is much more than just a mild accelerator.


"The reaction of hydroquinone with sulfite was not known when
D-76 was formulated nor was it discovered for about three
decades after.
The rise in pH was observed and a buffer of
borax and boric acid was substituted for the borax only in
the D-76d formula described in Capstaff's 1929 paper".

After using D-76 for many years, I found that I wasn`t using much of the U.S. gallon sizes quickly enough and the 1 litre size wasn`t very good value for money, so I decided to make my own from raw chemicals.
The one`s I tried were D-76 (basic formula) and D-76d to start with. I found the standard formula to match Kodak`s own D-76 for times and contrast, while the same times for D-76d gave me very under developed negatives.
I also made my own custom D-76 based on the Xtol patent which I published on apug in the Non-Staining Developers section which worked well. I think that "Modified DK-76" would have been a more appropriate description.

"I think the target pH of D-76 is about 8.7, I
can't remember what it is for D-23. In any case, if the
hydroquinone is left out of D-76 there is little difference
in activity as pointed out in the 1929 paper which explored
something like 30 variations of the formula. The one thing
that they did not try was a metol-sulfite developer. I think
perhaps the films of the time would have required too long a
development time with it or, perhaps, they just didn't think
of it".

I don`t see any benefits that D-76H might have over D-23. I don`t personally use D-23, but I have seen results from a photographer who uses D-23 replenished with DK-25R and the results are surprisingly very good.
I didn`t think I would ever like D-23, but I am now seriously considering using it the same way, full-strength and replenished having seen the results.
This fellows development times average around 6-8 minutes, depending on the film used.

"The paper was published in the _Transactions of the
Society of Motion Picture Engineers_ the quarterly
predecessor of the Journal. They are hard to find. I have a
copy because a friend with access to the MIT library Xeroxed
it for me. I will find the citation for you because it is a
very interesting paper. I don't think many other developers
were ever analysed as thoroughly as D-76".

I have seen this publication mentioned many times, and would appreciate a scanned copy (PDF) if that`s OK with you Richard.

"There was another variation of D-76 which was published
sometime about the mid 1930 at the time Kodak was pushing
Kodalk (sodium metaborate) as an alkali for all developers.
This one uses Kodalk instead of borax. Supposedly it Kodalk
had better buffering qualities than borax but it turned out
not to so the formula was never used much. It is identical
to the original D-76 but has 2 grams per liter of Kodalk
instead of borax. I think its possible that Packaged D-76 at
one time contained metaborate but the current stuff is a
variation of the buffered formula".

(See my comment on D-76d above).
Someone suggested to me, that DK-76 might have been useful for providing quicker development times than the standard formula, which might have been well over 10 minutes with the films back then.

"D-25, pubished about the same time as D-23 (early
1940s) is D-23 buffered to neutral pH with metabisulfite.
The lower activity makes it a very fine grain developer but
I think it had problems with dichroic fog with some films.
The old DK-20 formula, which contained sodium thiocyanate as
a silver halide solvent had serious problems with post-WW-2
emulsions and was discontinued as a packaged product. It is
an interesting formula but no longer practical. D-25 is just
as fine grain and works for more films. Microdol-X has a
proprietary formula although there are similar formulas in
some Kodak patents. It uses sodium chloride (common salt) as
the fine grain agent. I think Haist talks about this a
little but doesn't really give a full explanation of how it
works. I think he may have been constrained by being a
former Kodak employee not to disclose stuff Kodak considered
trade-secrets".

I think that a paper was published by R.W.Henn and J.I. Crabtree called "Elon Sulfite and Elon, Sulfite-Bisulfite developers" around 1944.
Now that Kodak have discontinued Microdol-X and that Perceptol is only available in 1 litre size packages, it might be worth exploring these types of developers further.


--
--
Richard Knoppow
Los Angeles, CA, USA

Thanks for your correspondence Richard.

Keith.

On the subject of buffering with borax or borax+boric acid, this thread may be of interest. There is also a post there by Ian Grant where he provides the formula for the Wellington Borax MQ developer which is actually an older formula than D-76. As Kodalk, wasn`t around back then, think of the formula as being D-50, the forerunner to DK-50.
Ian has worked as a chemical analyst and has an excellent source of photo-formulae..

Borax Project.