Not using a stop bath when developing film?

"Geoffrey S. Mendelson" wrote in message
...
In article
, The
Wogster wrote:

I never used a stop bath with film, but 3 20 second water
soaks,
and then used the fixer 1 shot. Never had a problem.

The use of a stop bath is really not needed for film, in
fact there have
been "monobath" (combined developer/fixer) products on the
market and
Edwal used to include instructions on how to use their
developers
as monobaths.

The main reason to use one is to force development to end
at a specific time
so that the results are the same, but using the same rinse
procedure will
each time do the same thing (with slightly different
results).

It's also to keep the alkeline developer from mixing with
the acid fixer.
The acid in the fixer acts as an emulsion hardner. Some
fixers include
it, some include it as an option (remember the two bottle
kodak rapid
fixer with hardner?) and some don't have it at all.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem Israel
IL Voice: 972-544-608-069 IL Fax: 972-2-648-1443 U.S.
Voice: 1-215-821-1838

Its not the acid in the fixing bath that does the
hardening. Common fixing baths use Potassium aluminum
sulfate, also known as White Alum, or just Alum. The alum
hardens the gelatin but works only over a fairly narrow
range of pH. The hardening remains at neutral pH but is
destroyed at much on the alkaline side of neutral. There are
other hardeners, mostly organic compounds, which are
effective hardeners in alkaline solution. These are common
in color processing.
Because the acid in an acid fixing bath reacts with the
thiosulfate and eventually decomposes it some means must be
provided to protect the thiosulfate. This is usually sodium
sulfite. The large amount of sulfite needed also tends to
prevent stains from the reaction products of carried over
developer.
Because modern stop baths were devised to work with or
without a stop bath they are heavily buffered by using a
combination of Acetic acid and Boric acid. This tends to
keep the pH of the bath in the right range for effective
hardening despite carried over developer or carried over
stop bath. This type of bath also tends to have less problem
from sludging of the hardener when the pH is off the right
value.
It should be noted that the ability of thiosulfate to fix
is independant of pH.
The odor from fixing baths is due to some decomposition
of the thiosufate by the acid. Making the bath less acid
will reduce the odor. Neutral fixing baths, essentially just
thiosulfate and sulfite, are very low odor.
Citric acid or sodium bisulfite or sodium metabisulfite
can be used for odorless stop baths. Citric acid is not
ideal for use with fixers using alum hardeners because it is
a sequestering agent for aluminum and will cause reduction
of hardening and may also cause sludging.
Many modern films do not require hardening so do not need
fixers which are acid. I seen no advantage whatever in
making a fixing bath alkaline but making neutral fixer is
fine. Also, the swelling of the emulsion will be less in a
neutral bath than in either an acid or alkaline bath.
There is an advantage in washing if the emulsion is
neutral when it it is washed. If an acid hardening fixer is
used a buffered sulfite wash aid, like Kodak Hypo Clearing
Agent, will adjust the pH to neutral and also eliminate the
binding effect of the alum on thiosulfate and fixer reaction
products. Wash times when the emulsion is treated in such a
bath are the same regardless of the type of fixing bath
used. In addition the sulfite acts as an ion exchanger for
thiosulfate so the wash is very much accelerated over what
one would have from a simple neutralizing bath without
sulfite.
I still think acid stop baths prevent more problems than
they cause but certainly a plain water rinse works if it
actually washes out the bulk of the developer.
BTW, someone mentioned monobath processing. Much of the
research on this was done by Grant Haist. He wrote a small
book called _The Monobath Manual_ (very hard to obtain now)
and also covers monobaths in his _Modern Photographic
Processing_. Monobaths are not simply a mixture of developer
and fixer. They must be very carefully formulated and
matched to a specific emulsion. They have some very
interesting properties, not least of which is very
considerable immunity to temperature and time variations.
Haist shows some examples suggesting the possible image
quality is very high. For some reason monobaths have never
become popular except for some special rapid access uses.


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

On Sat, 13 Nov 2004 03:27:18 -0800, "Richard Knoppow"
wrote:

Richard,

Great post as usual.

snip

Because modern stop baths were devised to work with or
without a stop bath they are heavily buffered by using a
combination of Acetic acid and Boric acid.

Perhaps you meant "fixing baths" ?

Monobaths are not simply a mixture of developer
and fixer. They must be very carefully formulated and
matched to a specific emulsion. They have some very
interesting properties, not least of which is very
considerable immunity to temperature and time variations.
Haist shows some examples suggesting the possible image
quality is very high. For some reason monobaths have never
become popular except for some special rapid access uses.

I think it's just as you indicated that they need to be
formulated for specific films and I would add that those formulas were
used one-shot and probably had limited stability due to the high
alkalinity. The formulas that I'm familiar with use hydroxide as an
accelerator. Perhaps there are other agents used ?

Regards,

John S. Douglas, Photographer - http://www.puresilver.org
Please remove the "_" when replying via email

On Sat, 13 Nov 2004 03:27:18 -0800, "Richard Knoppow"
wrote:

Richard,

Great post as usual.

snip

Because modern stop baths were devised to work with or
without a stop bath they are heavily buffered by using a
combination of Acetic acid and Boric acid.

Perhaps you meant "fixing baths" ?

Monobaths are not simply a mixture of developer
and fixer. They must be very carefully formulated and
matched to a specific emulsion. They have some very
interesting properties, not least of which is very
considerable immunity to temperature and time variations.
Haist shows some examples suggesting the possible image
quality is very high. For some reason monobaths have never
become popular except for some special rapid access uses.

I think it's just as you indicated that they need to be
formulated for specific films and I would add that those formulas were
used one-shot and probably had limited stability due to the high
alkalinity. The formulas that I'm familiar with use hydroxide as an
accelerator. Perhaps there are other agents used ?

Regards,

John S. Douglas, Photographer - http://www.puresilver.org
Please remove the "_" when replying via email

John wrote:

On Sat, 13 Nov 2004 03:27:18 -0800, "Richard Knoppow"
wrote:

Richard,

Great post as usual.

yeah I think he should consider adding a regular
joke line to his sig Who knew?


snip

Because modern stop baths were devised to work with or
without a stop bath they are heavily buffered by using a
combination of Acetic acid and Boric acid.

Perhaps you meant "fixing baths" ?

Unless one _is_ alkaline I'd use a stop.



Monobaths are not simply a mixture of developer
and fixer. They must be very carefully formulated and
matched to a specific emulsion. They have some very
interesting properties, not least of which is very
considerable immunity to temperature and time variations.
Haist shows some examples suggesting the possible image
quality is very high. For some reason monobaths have never
become popular except for some special rapid access uses.

I think it's just as you indicated that they need to be
formulated for specific films and I would add that those formulas were
used one-shot and probably had limited stability due to the high
alkalinity. The formulas that I'm familiar with use hydroxide as an
accelerator. Perhaps there are other agents used ?

Regards,

John S. Douglas, Photographer - http://www.puresilver.org
Please remove the "_" when replying via email

John wrote:

On Sat, 13 Nov 2004 03:27:18 -0800, "Richard Knoppow"
wrote:

Richard,

Great post as usual.

yeah I think he should consider adding a regular
joke line to his sig Who knew?


snip

Because modern stop baths were devised to work with or
without a stop bath they are heavily buffered by using a
combination of Acetic acid and Boric acid.

Perhaps you meant "fixing baths" ?

Unless one _is_ alkaline I'd use a stop.



Monobaths are not simply a mixture of developer
and fixer. They must be very carefully formulated and
matched to a specific emulsion. They have some very
interesting properties, not least of which is very
considerable immunity to temperature and time variations.
Haist shows some examples suggesting the possible image
quality is very high. For some reason monobaths have never
become popular except for some special rapid access uses.

I think it's just as you indicated that they need to be
formulated for specific films and I would add that those formulas were
used one-shot and probably had limited stability due to the high
alkalinity. The formulas that I'm familiar with use hydroxide as an
accelerator. Perhaps there are other agents used ?

Regards,

John S. Douglas, Photographer - http://www.puresilver.org
Please remove the "_" when replying via email

"Richard Knoppow" wrote

There are other hardeners, mostly organic compounds,
which are effective hardeners in alkaline solution.


Now days the integrity of incorporated hardeners is more of
a concern. Most B&W processing is done without hardeners added
to the chemistry.
Developers can be very alkaline. Have you any idea just how
alkaline they can be and not degrade the film's or paper's
incorporated hardener?
I've a notion that most films and papers are pre-process
hardened as fully as any in-process hardener will do, even more
so. Is that notion correct?
Perhaps pre-process hardening is less than if there were none
and the hardening left to an in-process hardener. Maybe a
combination of the two would result in the most hardened
emulsion possible. What do you think? Dan

John wrote in message . ..
On Sat, 13 Nov 2004 03:27:18 -0800, "Richard Knoppow"
wrote:

Richard,

Great post as usual.

snip

Because modern stop baths were devised to work with or
without a stop bath they are heavily buffered by using a
combination of Acetic acid and Boric acid.

Perhaps you meant "fixing baths" ?

Monobaths are not simply a mixture of developer
and fixer. They must be very carefully formulated and
matched to a specific emulsion. They have some very
interesting properties, not least of which is very
considerable immunity to temperature and time variations.
Haist shows some examples suggesting the possible image
quality is very high. For some reason monobaths have never
become popular except for some special rapid access uses.

I think it's just as you indicated that they need to be
formulated for specific films and I would add that those formulas were
used one-shot and probably had limited stability due to the high
alkalinity. The formulas that I'm familiar with use hydroxide as an
accelerator. Perhaps there are other agents used ?

Regards,

John S. Douglas, Photographer - http://www.puresilver.org
Please remove the "_" when replying via email


Of course, I meant fixing bath although buffered stop baths are
also possible and will have a longer life than a plain acetic or
citric acid bath.
Grant Haist goes quite deeply into monobaths, evidently this was a
subject of his research work at Kodak. Many monobaths do use sodium
hydroxide as the accelerator, the reason is simple: the developer must
compete with the fixer. Development must be completed before enough of
he halide is removed to destroy the image. Monobaths must also contain
a hardener. Haist has formulas with Glutaraldehyde but also lists a
number of oganic hardeners suitable for use in highly alkaline baths.
In both of his books Haist shows formulas optimized for Tri-X (roll
film) and Verichrome Pan, I think a couple of others but I am away
from my books at the moment. At least a couple of these formulas
include Phenidone as a primary developing agent.
I should point out that the hardener in fixing baths was intended
to compensate for the swelling caused by both the alkaline developer
and the acid fixer. Auxilliary hardeners are less necessary where the
pH of the solutions does not vary from neutral by much. Eliminating
the stop bath is attractive but there is still the problem of stopping
the development quickly and keeping developer from carrying over to a
neutral or alkaline fixing bath where it can continue development. A
long rinse in running water seems to be the solution. This is the
method used in alkaline color processing. Rinses are typically 1 to 3
minutes.
Where highly alkaline developers are used, such as lithographic
developers, it is common practice to use an anti-swelling stop bath.
Typically this has about 15 grams/liter of Sodium sulfate in it
(sulfate not sulfite). Sulfate is also used in tropical developers to
reduce emulsion swelling and slow the rate of development. Since many
B&W films, for instance T-Max, are now made to withstand 100F
processing such measures are not necessary for them. However, films
like Tri-X are still relatively sensitive to emulsion swelling. It was
also common in tropical processing and lith processing to use a
chrome-alum stop bath. Chrome alum is acid and is a very effective
hardener. However, it must operate at very low pH (around 2.0) so is
difficult to incorporate into fixing baths although there are chrome
alum fixing baths. Its use is probably not necessary for any film
these days.
With all the talk about alkaline processing and eliminating stop
baths it seems to have gotten lost that this procedure has been used
with completely satisfactory results for many decades. The proper use
of an acid stop bath stops development quickly and prevents carryover
of active developer into the fixing bath. It also prevents the
possible generation of developer stain where it is allowed to continue
in a bath without sulfite.
It also seems to me than in reading the reasons for not using acid
stop baths I am really seeing complaints of problems from bad
practice. Even complaints about odor can be solved by using acids
other than Acetic acid.
Pin holes are extremely unlikely to be caused by any conventional
packaged developer or fixer. For one thing modern emulsions are not
very vulnerable to it and very few current film developers use
carbonate, the villan in outgassing. A pinhole is an actual disruption
of the emulsion. I suspect that very often what people are seeing are
small clear spots caused by dust on the negative. Pin holes CAN occur
because of coating problems. These exist in the emulsion from the
manufacturer. A very great deal of research and technical development
has gone into making very consistent coatings. This is very well
established technology but even the best manufacturers may have
problems especially in these days of low sales and cost cutting.
Personally, I suspect the whole movement to use alkaline processing
is a sort of belief in black magic. Well, folks, there just isn't any
black magic in photographic chemistry anymore. Even emulsion making,
once one of the most closely guarded proprietary secrets in any
industry, are now public record and anyone who is willing to do some
research, AND has a decent understanding of organic and colloid
chemistry, can find out how its done.
Now, watch the flames come:-)

Richard Knoppow
Los Angeles, CA, USA

John wrote in message . ..
On Sat, 13 Nov 2004 03:27:18 -0800, "Richard Knoppow"
wrote:

Richard,

Great post as usual.

snip

Because modern stop baths were devised to work with or
without a stop bath they are heavily buffered by using a
combination of Acetic acid and Boric acid.

Perhaps you meant "fixing baths" ?

Monobaths are not simply a mixture of developer
and fixer. They must be very carefully formulated and
matched to a specific emulsion. They have some very
interesting properties, not least of which is very
considerable immunity to temperature and time variations.
Haist shows some examples suggesting the possible image
quality is very high. For some reason monobaths have never
become popular except for some special rapid access uses.

I think it's just as you indicated that they need to be
formulated for specific films and I would add that those formulas were
used one-shot and probably had limited stability due to the high
alkalinity. The formulas that I'm familiar with use hydroxide as an
accelerator. Perhaps there are other agents used ?

Regards,

John S. Douglas, Photographer - http://www.puresilver.org
Please remove the "_" when replying via email


Of course, I meant fixing bath although buffered stop baths are
also possible and will have a longer life than a plain acetic or
citric acid bath.
Grant Haist goes quite deeply into monobaths, evidently this was a
subject of his research work at Kodak. Many monobaths do use sodium
hydroxide as the accelerator, the reason is simple: the developer must
compete with the fixer. Development must be completed before enough of
he halide is removed to destroy the image. Monobaths must also contain
a hardener. Haist has formulas with Glutaraldehyde but also lists a
number of oganic hardeners suitable for use in highly alkaline baths.
In both of his books Haist shows formulas optimized for Tri-X (roll
film) and Verichrome Pan, I think a couple of others but I am away
from my books at the moment. At least a couple of these formulas
include Phenidone as a primary developing agent.
I should point out that the hardener in fixing baths was intended
to compensate for the swelling caused by both the alkaline developer
and the acid fixer. Auxilliary hardeners are less necessary where the
pH of the solutions does not vary from neutral by much. Eliminating
the stop bath is attractive but there is still the problem of stopping
the development quickly and keeping developer from carrying over to a
neutral or alkaline fixing bath where it can continue development. A
long rinse in running water seems to be the solution. This is the
method used in alkaline color processing. Rinses are typically 1 to 3
minutes.
Where highly alkaline developers are used, such as lithographic
developers, it is common practice to use an anti-swelling stop bath.
Typically this has about 15 grams/liter of Sodium sulfate in it
(sulfate not sulfite). Sulfate is also used in tropical developers to
reduce emulsion swelling and slow the rate of development. Since many
B&W films, for instance T-Max, are now made to withstand 100F
processing such measures are not necessary for them. However, films
like Tri-X are still relatively sensitive to emulsion swelling. It was
also common in tropical processing and lith processing to use a
chrome-alum stop bath. Chrome alum is acid and is a very effective
hardener. However, it must operate at very low pH (around 2.0) so is
difficult to incorporate into fixing baths although there are chrome
alum fixing baths. Its use is probably not necessary for any film
these days.
With all the talk about alkaline processing and eliminating stop
baths it seems to have gotten lost that this procedure has been used
with completely satisfactory results for many decades. The proper use
of an acid stop bath stops development quickly and prevents carryover
of active developer into the fixing bath. It also prevents the
possible generation of developer stain where it is allowed to continue
in a bath without sulfite.
It also seems to me than in reading the reasons for not using acid
stop baths I am really seeing complaints of problems from bad
practice. Even complaints about odor can be solved by using acids
other than Acetic acid.
Pin holes are extremely unlikely to be caused by any conventional
packaged developer or fixer. For one thing modern emulsions are not
very vulnerable to it and very few current film developers use
carbonate, the villan in outgassing. A pinhole is an actual disruption
of the emulsion. I suspect that very often what people are seeing are
small clear spots caused by dust on the negative. Pin holes CAN occur
because of coating problems. These exist in the emulsion from the
manufacturer. A very great deal of research and technical development
has gone into making very consistent coatings. This is very well
established technology but even the best manufacturers may have
problems especially in these days of low sales and cost cutting.
Personally, I suspect the whole movement to use alkaline processing
is a sort of belief in black magic. Well, folks, there just isn't any
black magic in photographic chemistry anymore. Even emulsion making,
once one of the most closely guarded proprietary secrets in any
industry, are now public record and anyone who is willing to do some
research, AND has a decent understanding of organic and colloid
chemistry, can find out how its done.
Now, watch the flames come:-)

Richard Knoppow
Los Angeles, CA, USA

(Richard Knoppow) wrote in message . com...

Personally, I suspect the whole movement to use alkaline processing
is a sort of belief in black magic. Well, folks, there just isn't any
black magic in photographic chemistry anymore. Even emulsion making,
once one of the most closely guarded proprietary secrets in any
industry, are now public record and anyone who is willing to do some
research, AND has a decent understanding of organic and colloid
chemistry, can find out how its done.
Now, watch the flames come:-)

Richard Knoppow
Los Angeles, CA, USA


1. A test performed in 1966 by Popular Photography magazine showed NO
difference between the grain of Tri-X processed with or without a stop
bath, magnified under a microscope.

2. I quit using stop bath because I don't think it is the best way to
stop development evenly. For about 10 years now I simply pour several
large containers of tempered water into my Paterson tanks and flush
the developer out. I never have streaks anymore, which I sometimes
experienced with stop bath.

On 14 Nov 2004 04:43:30 -0800, (Richard
Knoppow) wrote:

Well, folks, there just isn't any
black magic in photographic chemistry anymore.

Doggone it ! Ansel beat me to all that Black Magic developer
!!


Regards,

John S. Douglas, Photographer - http://www.puresilver.org
Please remove the "_" when replying via email