Target ph for phenidone

Is there a target ph for phenidone-hydroquinone superadditivity? I ask
because I don't see why adding a little phenidone to "imporved" D76 wouldn't
improve the developers effective iso's.
-Lew

"Lew" wrote in message
t...
Is there a target ph for phenidone-hydroquinone
superadditivity? I ask because I don't see why adding a
little phenidone to "imporved" D76 wouldn't improve the
developers effective iso's.
-Lew
I don't know if the super additivity works only in some
pH window. Probably a pretty wide one because existing
formulas for PQ developers exist for D-76 like ones and
print developers. For instance packaged Ilford DD-X,
Microphen,ID-68, Bromophen, are all PQ developers with
different pH, increasing in the order given from about 8.2
to about 10.5. The pH is similar to MQ formulas for the same
purposes.
I don't think there will be an advantage to adding
Phenidone to D-76 but a D-76 type developer (i.e., P-Q and
Borax) will yeild slightly higher speed. DD-X is an example,
it gives higher speed and about the same grain as packaged
D-76. ID-68 has somewhat higher pH than DDX or Microphen and
yeilds slightly coarser grain. DDX and Microphen are not the
same although both are P-Q relatives of D-76.


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

Well, I am interested in a D76 type PQ developer because I'm very
comfortable with the grain structures I get with D76 as opposed to
Microphen, but I can't seem to support established iso's in D76. Is there a
published formula for a DDX-like soup? I'd be especially interested in
formulas with published replenishers.
-LS
"Richard Knoppow" wrote in message
nk.net...
"Lew" wrote in message
t...
Is there a target ph for phenidone-hydroquinone superadditivity? I ask
because I don't see why adding a little phenidone to "imporved" D76
wouldn't improve the developers effective iso's.
-Lew
I don't know if the super additivity works only in some pH window.
Probably a pretty wide one because existing formulas for PQ developers
exist for D-76 like ones and print developers. For instance packaged
Ilford DD-X, Microphen,ID-68, Bromophen, are all PQ developers with
different pH, increasing in the order given from about 8.2 to about 10.5.
The pH is similar to MQ formulas for the same purposes.
I don't think there will be an advantage to adding Phenidone to D-76 but
a D-76 type developer (i.e., P-Q and Borax) will yeild slightly higher
speed. DD-X is an example, it gives higher speed and about the same grain
as packaged D-76. ID-68 has somewhat higher pH than DDX or Microphen and
yeilds slightly coarser grain. DDX and Microphen are not the same although
both are P-Q relatives of D-76.


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

I forgot to mention in case you didn't know, Dimezone-S is a version of
phenidone that has advantages in solubility and longer life in solution.

"Lew" wrote in message
...
Well, I am interested in a D76 type PQ developer because
I'm very comfortable with the grain structures I get with
D76 as opposed to Microphen, but I can't seem to support
established iso's in D76. Is there a published formula for
a DDX-like soup? I'd be especially interested in formulas
with published replenishers.
-LS
"Richard Knoppow" wrote in
message
nk.net...
"Lew" wrote in message
t...

Snipping here.............

DDX is a proprietary formula. While the principle
ingredients appear in the MSDS there may be some present in
too low a concentration and in any case one would have to
guess at the amounts.
The closest to what you are looking for is probably home
made Xtol even though it uses Ascorbic acid instead of
Hydroquinone. A good formula appears on Ruyji Suzuki's site
at http://www.silvergrain.org In particular
http://wiki.silvergrain.org/wiki/index.php/Film_Developer_Recommendations#DS-10_Fine_grain_developer

A note on film speed. The ISO method used for determining
film speed is specific for the contrast index given in the
standard and for the developer used by the manufacturer in
making the test. While standard developers were given in
previous versions of the standard the current one has none.
Any developer can be used provided it is given with the
speed. A change in the developer or a change in the target
CI will result in a change in effective speed.
For nearly 80 years D-76 has been the standard to which
other developers are compared. It is reasonably fine grain
and delivers about the maximum speed possible from an MH
developer with no restrainer. Phenidone developers are
capable of yeilding as much as 3/4 stop greater speed for
the same contrast index. Not all Phenidone developers do
this, the formula has to be right. Some common developers
deliver less speed than D-76. For example Kodak Microdol-X
and Ilford Perceptol, both extra-fine-grain developers,
yeild about 3/4 stop less speed than D-76 for the same CI,
when used full strength (when diluted both speed and grain
are increased). This is about the limit of the range with
exception of the historical p-phenelynediamine super fine
grain formulas which can lose something like 5 stops of
speed. These have no advantage over Microdol-X/Perceptol,
and will not work on modern films anyway, at least not
unless you like lots of dichroic fog.
The film curve may also have an effect on perceived film
speed. Long toe films, that is, films with low contrast in
the shadows, may seem to be slower than a film of the same
ISO speed but with a shorter toe. The ISO method includes a
shift in measurement point up the toe to try to eliminate
this effect but it seems to be there nonetheless.
Also, the preamble to the standard makes it clear that
the speed found best in practice may be different than the
ISO speed because processing of B&W is not standardized.
There are many variables. The best the ISO standard can do
is to give some basis for comparing films for gross speed.
I.e. 400T-Max requires about one forth the exposure of
100T-Max, but only _about_.
Also, there is no safety factor in the ISO standard. Most
films will have somewhat better shadow detail and better
overall tone rendition if some exposure is added, perhaps
half to one stop.
Ryuji's formula will give you about the same speed as
Xtol, DDX, or Microphen, with about the same grain as Xtol.
Its advantage is that Ryuji has some understanding of why
Xtol sometimes fails and has included a couple of
ingredients to help prevent the problem. Since Ascorbic acid
is environmentally safer than Hydroquinone and works as well
in this application there is no reason to continue using
Hydroquinone, unless you have a lifetime supply of it.
An historical note: Perhaps the problem with the ISO
standard will be made clearer if one looks at its history.
About 1943 the American Standards Association, now ANSI,
adopted a version of a film speed standard which had been in
use at Kodak for a few years. This standard, called Kodak
Speeds, was designed by Loyd A. Jones, and associates, at
Kodak Labs. It was based on some twenty years of research
into photographic tone rendition. Jones wanted the minimum
exposure that resulted in an "excellent print". The idea of
going for the minimum is that film grain generally increases
and sharpness decreases with density. This was a much more
serious problem for the films of the 1930s and 1940s than it
is now. Jones found that once the minimum exposure had been
given additonal exposure had little or no difference on tone
rendition up to many stops, depending on the film. He found
that for the films he tested that the minimum was when the
speed point was set on the toe where the toe contrast
(gamma) as 1/3rd of the overall straight-line contrast. When
the ASA adopted this sytem as a national standard they did
two things: one was to use a constant in the calculation
that would put the speed numbers midway between the two most
widely used speed systems then in use; the Weston and the
General Electric numbers. The other was to throw out Jones
idea of minimum exposure. Kodak and others were worried
about making sure amateurs would get printable images. Since
there is very little latitude for error on the low exposure
side, but lots on the high exposure side, they opted to add
a fudge factor of 2, essentially cutting the speeds in half.
This resulted in overly dense negatives. In fact, for years
Kodak instructions were that if you knew what you were doing
you could double the film speeds from the ASA speed.
The Jones minimum usable gradient method proved very
difficult to measure in practice, at least for users with
less sophisticated resources than Kodak. So, in 1958, the
ASA discontinued the use of the Jones/Kodak speed method in
favor of the new DIN method. This must be distinguished from
the DIN method in use during the 1930s and 1940s, it was
based on a different principle. The new DIN method relies on
developing the film to a specified contrast index and
meauring over a specified range of densities. The speed
point is set at a density which is log 0.1 higher than the
combination of fog and support (or base) density. The
inclusion of base density is necessary because some films,
particularly 35mm films, have a rather dense pigment in the
support to reduce propagation of light through the support.
The DIN method was modified in one important respect.
That was the addition of a constant such that the actual
minimum exposure was moved up the toe from the log 0.1 point
to a point approximating Jones criteria of having a minimum
gamma of 1/3rd the straight line gamma. The ISO tested about
100 negative stocks and found that this condition would be
achieved in nearly all of them by multiplying the speed
obtained from the speed point by 0.8. The 2x safty factor of
the old ASA standard was eliminated. So, on the day the new
ASA standard was adopted all films doubled in speed! This
method is still the one in use today although the standard
has been ammended several times to provide better clarity
and reliability. The last emmendation was to drop the use of
a standard developer formula, mainly because the two
specified in the standard had little relationship to those
used in practice, and allow the use of any developer
provided it was specified along with the resulting speed.
The ISO standrd applies _only_ to black and white silver
halide negative film for still cameras. A differnt standard
is used for films for other applications, such as motion
picture film. A different standard is also used for color
films. Modern color films are very standardized in
processing so a more exact statement of speed can be made.
Reversal films are developed to completion and have almost
no latitude for exposure variation so yet another standard
is used for them. Other special use films, such as aerial,
x-ray, process, all have their own standards often yeilding
rather different speeds than the familiar B&W ISO method
would.
All this is a bit off the topic of developers, but since
one of the criteria of the original poster was film speed I
thought this rather detailed explanation might be helpful.


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

Lew wrote:

Is there a target ph for ... ?

Lew


That's what I'd still like to know. Not only agents
acting alone but also in combination. I got to thinking
along that line a few years ago when working with D-23
types; metol - sulfite.

I thought perhaps the metol was not as activated
so much as to fully exploit the emulsion's inherent speed.
At a low enough ph very little or no development will occure.
What does, I expect, occures with the more exposed portions
leaving the little exposed areas totaly undeveloped. So, the
speed of the film is effectively reduced.

Bicarbonated vs carbonated single agent developer testing would
shed some light. Testing I've not gotten around to. Dan

wrote in message
oups.com...
Lew wrote:

Is there a target ph for ... ?

Lew


That's what I'd still like to know. Not only agents
acting alone but also in combination. I got to thinking
along that line a few years ago when working with D-23
types; metol - sulfite.

I thought perhaps the metol was not as activated
so much as to fully exploit the emulsion's inherent speed.
At a low enough ph very little or no development will
occure.
What does, I expect, occures with the more exposed
portions
leaving the little exposed areas totaly undeveloped. So,
the
speed of the film is effectively reduced.


What makes you think this happens?

Bicarbonated vs carbonated single agent developer testing
would
shed some light. Testing I've not gotten around to. Dan

I have never seen a developer with bicarbonate except as a
buffering agent.

Metol will develop even in slightly acid conditions but
very slowly. It works fine at neutral pH as in Kodak D-25.
If it worked as you envision it would produce high
contrast images where, in fact, D-23 has good shadow detail
and yeilds about the same speed as D-76. The difference is
developing time for the same gamma, D-23 takes longer.
Adding Borax will increase the activity and decrease the
developing time. An example is very old DuPont formula for
motion picture negative film. This was the result in
DuPont's research into D-76 type developers.

DuPont Formula [1]

Water (at 125F or 52C) 750.0 ml
Metol 5.0 grams
Sodium Sulfite, dessicated 75.0 grams
Borax, granulated 5.0 grams
Water to make 1.0 liter

Development times are similar to D-76. Because this
developer does not contain Hydroquinone its activity does
not rise on storage.

Bromide has an effect on film speed. As developer is used
it accumulates reaction products. One of these is bromide.
Bromide tends to restrain the development of fog grains but
at some point will also restrain the development of halide
grains with little exposure. For this reason used developer
will have the effect of lowered film speed even when
developement is carried out longer. Metol is relatively less
sensitive to bromide than Hydroquinone. At the low pH of
D-76, D-23, D-25, and the above developer, metol does not
produce much fogging so bromide is not necessary. When a
carbonate is used bromide becomes necessary because the
higher pH causes more fog.
At the pH of D-76 Hydroquinone is nearly inactive as a
developing agent. Its function is regeneration of the Metol.
This results in somewhat greater capacity for D-76 than for
the DuPont formula or D-23. However, the slow reaction
between Hydroquinone and sulfite produces a small amount of
hydroxide which causes the pH to rise over a period of time.
Kodak's cure for this was to buffer the developer by using a
combination of Borax and Boric acid. Current packaged D-76
is of this type. DuPont found that the addition of
Hydroquinone had no practical advantage and just left it out
although later DuPont developers did include it.
It should be noted that highly active developers like
Dektol (D-72) do not produce high film speed due to the
necessity for considerable bromide.
The literature is filled with research on all sorts of
developers and combinations. Such publications as _The
Journal of the Society of Motion Picture and Television
Engineers_ and _Photographic Science and Engineering_ as
well as extensive patent data will reveal all.

1. "Borax Developer Characteristics" H. W. Moyse and D. R
..White (DuPont Redpath Labs), _Transactions of the Society
of Motion Picture Engineers_ Vol. XIII, No. 38, 1929 p.445


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

Richard Knoppow wrote:

wrote in message
roups.com...


Lew wrote:

Is there a target ph for ... ?

Lew



That's what I'd still like to know. Not only agents
acting alone but also in combination. I got to thinking
along that line a few years ago when working with D-23
types; metol - sulfite.

I thought perhaps the metol was not as activated
so much as to fully exploit the emulsion's inherent speed.
At a low enough ph very little or no development will
occure.
What does, I expect, occures with the more exposed
portions
leaving the little exposed areas totaly undeveloped. So,
the
speed of the film is effectively reduced.




What makes you think this happens?



Bicarbonated vs carbonated single agent developer testing
would
shed some light. Testing I've not gotten around to. Dan



I have never seen a developer with bicarbonate except as a
buffering agent.

Metol will develop even in slightly acid conditions but
very slowly. It works fine at neutral pH as in Kodak D-25.
If it worked as you envision it would produce high
contrast images where, in fact, D-23 has good shadow detail
and yeilds about the same speed as D-76. The difference is
developing time for the same gamma, D-23 takes longer.
Adding Borax will increase the activity and decrease the
developing time. An example is very old DuPont formula for
motion picture negative film. This was the result in
DuPont's research into D-76 type developers.

DuPont Formula [1]

Water (at 125F or 52C) 750.0 ml
Metol 5.0 grams
Sodium Sulfite, dessicated 75.0 grams
Borax, granulated 5.0 grams
Water to make 1.0 liter

Development times are similar to D-76. Because this
developer does not contain Hydroquinone its activity does
not rise on storage.

Bromide has an effect on film speed. As developer is used
it accumulates reaction products. One of these is bromide.
Bromide tends to restrain the development of fog grains but
at some point will also restrain the development of halide
grains with little exposure. For this reason used developer
will have the effect of lowered film speed even when
developement is carried out longer. Metol is relatively less
sensitive to bromide than Hydroquinone. At the low pH of
D-76, D-23, D-25, and the above developer, metol does not
produce much fogging so bromide is not necessary. When a
carbonate is used bromide becomes necessary because the
higher pH causes more fog.
At the pH of D-76 Hydroquinone is nearly inactive as a
developing agent. Its function is regeneration of the Metol.
This results in somewhat greater capacity for D-76 than for
the DuPont formula or D-23. However, the slow reaction
between Hydroquinone and sulfite produces a small amount of
hydroxide which causes the pH to rise over a period of time.
Kodak's cure for this was to buffer the developer by using a
combination of Borax and Boric acid. Current packaged D-76
is of this type. DuPont found that the addition of
Hydroquinone had no practical advantage and just left it out
although later DuPont developers did include it.
It should be noted that highly active developers like
Dektol (D-72) do not produce high film speed due to the
necessity for considerable bromide.
The literature is filled with research on all sorts of
developers and combinations. Such publications as _The
Journal of the Society of Motion Picture and Television
Engineers_ and _Photographic Science and Engineering_ as
well as extensive patent data will reveal all.

1. "Borax Developer Characteristics" H. W. Moyse and D. R
.White (DuPont Redpath Labs), _Transactions of the Society
of Motion Picture Engineers_ Vol. XIII, No. 38, 1929 p.445




With regard to the original question, there are apparently conditions
under which metol and phenidone are antagonistic. I read about it many
years ago, and experienced it one night when my MQ or MC, I don't
remember which, was getting weak so I added a dash of phenidone. It
practically killed the developer.

The combination of metol or phenidone, ascorbic acid and hydroquinone or
catechol is very active when the right proportions are used. Sulfite is
not required.

Actually, this is exactly what I had planned for some processing I have
to do tomorrow: Add a small amount of phenidone to D76 1:1. Now, if I
understand Patrick correctly, I'd better abandon that idea. I know that the
hydroquinine in D76 doesn't do much, but that it is superadditive with
phenidone. It seemed obvious to me that someone would have thought of adding
phenidone to D76, so I couldn't understand why I couldn't find anything to
read about it. Maybe the ph of D76 was too low.
I've gotten into this mind set because a) I like full or increased film
speed and b) I use a diffuser enlarger. With the diffuser and recommended
time/temps I've had to use grade 3/4 papers as my standard. This doesn't
leave me much room to increase contrast during printing. My current line of
experiments with different developers centers around increasing recommended
times aprox 20%, so I can get negs that will print properly on #2 paper (I'm
also looking into staining developers to keep highlights from blocking up.)
This increase with XTOL type developers seems to muddy up highlights. I
prefer the look of D76, but miss the added speed of phenidone based
developers.

"PATRICK GAINER" wrote in message
...
Richard Knoppow wrote:

wrote in message
groups.com...


Lew wrote:

Is there a target ph for ... ?

Lew



That's what I'd still like to know. Not only agents
acting alone but also in combination. I got to thinking
along that line a few years ago when working with D-23
types; metol - sulfite.

I thought perhaps the metol was not as activated
so much as to fully exploit the emulsion's inherent speed.
At a low enough ph very little or no development will
occure.
What does, I expect, occures with the more exposed
portions
leaving the little exposed areas totaly undeveloped. So,
the
speed of the film is effectively reduced.




What makes you think this happens?



Bicarbonated vs carbonated single agent developer testing
would
shed some light. Testing I've not gotten around to. Dan



I have never seen a developer with bicarbonate except as a
buffering agent.

Metol will develop even in slightly acid conditions but
very slowly. It works fine at neutral pH as in Kodak D-25.
If it worked as you envision it would produce high
contrast images where, in fact, D-23 has good shadow detail
and yeilds about the same speed as D-76. The difference is
developing time for the same gamma, D-23 takes longer.
Adding Borax will increase the activity and decrease the
developing time. An example is very old DuPont formula for
motion picture negative film. This was the result in
DuPont's research into D-76 type developers.

DuPont Formula [1]

Water (at 125F or 52C) 750.0 ml
Metol 5.0 grams
Sodium Sulfite, dessicated 75.0 grams
Borax, granulated 5.0 grams
Water to make 1.0 liter

Development times are similar to D-76. Because this
developer does not contain Hydroquinone its activity does
not rise on storage.

Bromide has an effect on film speed. As developer is used
it accumulates reaction products. One of these is bromide.
Bromide tends to restrain the development of fog grains but
at some point will also restrain the development of halide
grains with little exposure. For this reason used developer
will have the effect of lowered film speed even when
developement is carried out longer. Metol is relatively less
sensitive to bromide than Hydroquinone. At the low pH of
D-76, D-23, D-25, and the above developer, metol does not
produce much fogging so bromide is not necessary. When a
carbonate is used bromide becomes necessary because the
higher pH causes more fog.
At the pH of D-76 Hydroquinone is nearly inactive as a
developing agent. Its function is regeneration of the Metol.
This results in somewhat greater capacity for D-76 than for
the DuPont formula or D-23. However, the slow reaction
between Hydroquinone and sulfite produces a small amount of
hydroxide which causes the pH to rise over a period of time.
Kodak's cure for this was to buffer the developer by using a
combination of Borax and Boric acid. Current packaged D-76
is of this type. DuPont found that the addition of
Hydroquinone had no practical advantage and just left it out
although later DuPont developers did include it.
It should be noted that highly active developers like
Dektol (D-72) do not produce high film speed due to the
necessity for considerable bromide.
The literature is filled with research on all sorts of
developers and combinations. Such publications as _The
Journal of the Society of Motion Picture and Television
Engineers_ and _Photographic Science and Engineering_ as
well as extensive patent data will reveal all.

1. "Borax Developer Characteristics" H. W. Moyse and D. R
.White (DuPont Redpath Labs), _Transactions of the Society
of Motion Picture Engineers_ Vol. XIII, No. 38, 1929 p.445




With regard to the original question, there are apparently conditions
under which metol and phenidone are antagonistic. I read about it many
years ago, and experienced it one night when my MQ or MC, I don't
remember which, was getting weak so I added a dash of phenidone. It
practically killed the developer.

The combination of metol or phenidone, ascorbic acid and hydroquinone or
catechol is very active when the right proportions are used. Sulfite is
not required.

Richard Knoppow wrote:

wrote

Lew wrote:

Is there a target ph for ... ? Lew


That's what I'd still like to know. Not only agents
acting alone but also in combination. I got to thinking
along that line a few years ago when working with D-23
types; metol - sulfite.

I thought perhaps the metol was not as activated
so much as to fully exploit the emulsion's inherent speed.
At a low enough ph very little or no development will
occure.
What does, I expect, occures with the more exposed
portions
leaving the little exposed areas totaly undeveloped. So,
the
speed of the film is effectively reduced.


What makes you think this happens?


For one thing D-25 with it's low ph yields a speed hit. For
a second thing I think I'm doing better with a carbonated metol
developer than sulfited only. For a third thing I've tested D-23 with
paper and found that Ansco 120 results can be produced by
increasing the print exposure quite a bit.

Like I say I've not really pinned it down but I think even the
little evidence encountered so far point to a relationship tixt
ph and agent activation. I'm interested in real world results
and not concerned with day long developing.



Bicarbonated vs carbonated single agent developer testing
would shed some light. Testing I've not gotten around to. Dan

I have never seen a developer with bicarbonate except as a
buffering agent.


With a water stop it may be OK. How about D-25 BiC?
Compound with little sulfite and activate with bicarbonate. A
water stop only should likely be used. Expect Very Fine
grain and Exceptional resolution. But then again will
there be a speed hit due to low ph?


Metol will develop even in slightly acid conditions but
very slowly. It works fine at neutral pH as in Kodak D-25.


It works fine and is a Very Fine grain High sulfite Low ph
developer. Don't forget to double the exposure. Dan