HCA test?

Greetings everyone:

So, I'm back in my darkroom after a long summer and decided
to use up some old chems. Things are generally long-lived in
my basememt and I've got some 5 gal. packages of KHCA. These
are old -- possibly 5 - 10 years.

The general 'is it good v. bad' is the color of the powder,
though I've never actually seen sulfite turn brown. The oldest
looking package was still a sugar white. Some have said if it
has a sulfur dioxide smell it's bad Anyway no smell and mixed
to a clear liquid.

I've got a lot of this stuff and I could do some HT-2 tests (fix,
hypoclear, short wash, test for fixer residue) to assess the
efficaciousness of the old hypoclear+wash but was wondering
(richard or anyone else...) is there any chemically viable
known method to test the HCA solution directly.

TIA Tom Phillips

Tom Phillips wrote


was wondering ... is there any chemically viable
known method to test the HCA solution directly.


Problem is it's Kodak HCA. There is no knowing precisely
it's composition at start.
You could compare the old with some new using permanganate.
You will have some idea of how much it has oxidized. Dan

Dan Quinn wrote:
Tom Phillips wrote


was wondering ... is there any chemically viable
known method to test the HCA solution directly.



Problem is it's Kodak HCA. There is no knowing precisely
it's composition at start.
You could compare the old with some new using permanganate.
You will have some idea of how much it has oxidized. Dan

KHCA contains a lot of sodium sulphite, some sodium metabisulphite, and
perhaps a sequesterant.

The simplest solution (no pun intended) is to use the stuff one-shot, or
nearly one-shot. When processing film, I use it one-shot. When processing
paper (and I do it manually in trays), I dump it when I am done or in 4
hours, whichever happens first.

This may be wasteful, but I need not worry about exhausting it at the rate
I make prints.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 10:15:00 up 7 days, 21:19, 4 users, load average: 5.49, 5.76, 5.37

"Tom Phillips" wrote in message
...
Greetings everyone:

So, I'm back in my darkroom after a long summer and
decided
to use up some old chems. Things are generally long-lived
in
my basememt and I've got some 5 gal. packages of KHCA.
These
are old -- possibly 5 - 10 years.

The general 'is it good v. bad' is the color of the
powder,
though I've never actually seen sulfite turn brown. The
oldest
looking package was still a sugar white. Some have said if
it
has a sulfur dioxide smell it's bad Anyway no smell and
mixed
to a clear liquid.

I've got a lot of this stuff and I could do some HT-2
tests (fix,
hypoclear, short wash, test for fixer residue) to assess
the
efficaciousness of the old hypoclear+wash but was
wondering
(richard or anyone else...) is there any chemically viable
known method to test the HCA solution directly.

TIA Tom Phillips

The principal ingredient in KHCA is Sodium sulfite. When
it is oxidezed sulfite become sulfate. Sodium sulfate does
no harm but is not nearly as effective as a wash aid as is
sulfite. The chemical does not change color when oxidized.
The brown in developers is an oxidation product of either
the Metol or Hydroquinone, since wash aid contains neither
it does not turn color.
I am not a chemist so I don't know what the test is for
sulfite nor if the presence of the metabisulfite, the other
key ingredient, would affect it. Probably the easiest test
is a wash test. Film should wash out in about five minutes
when treated in KHCA and in about 30 minutes when not
treated (hardening fixer). A sulfide test will tell if the
KHCA is working. The stuff does not have a long life when
mixed but unless the Kodak bags are damaged it should have a
shelf life of at least two years.
I agree about the Sulfur dioxide odor, it would indicate
decomposition of the sulfite but not oxidation, so it could
be odor free and still not effective.
Sorry I can't do better but perhaps there is a genuine
chemist following this group who can give a method of
analysing the stuff.


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

"Tom Phillips" wrote in message
...
Greetings everyone:

So, I'm back in my darkroom after a long summer and
decided
to use up some old chems. Things are generally long-lived
in
my basememt and I've got some 5 gal. packages of KHCA.
These
are old -- possibly 5 - 10 years.

The general 'is it good v. bad' is the color of the
powder,
though I've never actually seen sulfite turn brown. The
oldest
looking package was still a sugar white. Some have said if
it
has a sulfur dioxide smell it's bad Anyway no smell and
mixed
to a clear liquid.

I've got a lot of this stuff and I could do some HT-2
tests (fix,
hypoclear, short wash, test for fixer residue) to assess
the
efficaciousness of the old hypoclear+wash but was
wondering
(richard or anyone else...) is there any chemically viable
known method to test the HCA solution directly.

TIA Tom Phillips

The principal ingredient in KHCA is Sodium sulfite. When
it is oxidezed sulfite become sulfate. Sodium sulfate does
no harm but is not nearly as effective as a wash aid as is
sulfite. The chemical does not change color when oxidized.
The brown in developers is an oxidation product of either
the Metol or Hydroquinone, since wash aid contains neither
it does not turn color.
I am not a chemist so I don't know what the test is for
sulfite nor if the presence of the metabisulfite, the other
key ingredient, would affect it. Probably the easiest test
is a wash test. Film should wash out in about five minutes
when treated in KHCA and in about 30 minutes when not
treated (hardening fixer). A sulfide test will tell if the
KHCA is working. The stuff does not have a long life when
mixed but unless the Kodak bags are damaged it should have a
shelf life of at least two years.
I agree about the Sulfur dioxide odor, it would indicate
decomposition of the sulfite but not oxidation, so it could
be odor free and still not effective.
Sorry I can't do better but perhaps there is a genuine
chemist following this group who can give a method of
analysing the stuff.


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

"Richard Knoppow"

The principal ingredient in KHCA is Sodium sulfite. When
it is oxidezed sulfite become sulfate. Sodium sulfate does
no harm but is not nearly as effective as a wash aid as is
sulfite. The chemical does not change color when oxidized.

I believe NaSO3 - NaSO4 only takes place in the presence of
water. If the powder is dry then it should be OK.

The pH of a sulfite solution should drop as it oxidizes to
sulfate. I do not know what the pH values would be.
pH paper may be sensitive enough to pick up the change.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Jean-David Beyer wrote:

Dan Quinn wrote:
Tom Phillips wrote


was wondering ... is there any chemically viable
known method to test the HCA solution directly.

Problem is it's Kodak HCA. There is no knowing precisely
it's composition at start.
You could compare the old with some new using permanganate.
You will have some idea of how much it has oxidized. Dan

Don't have permanganate, however. Unfortunately I chose not to get
it with a recent order at formulary...

KHCA contains a lot of sodium sulphite, some sodium metabisulphite, and
perhaps a sequesterant.

The simplest solution (no pun intended) is to use the stuff one-shot, or
nearly one-shot. When processing film, I use it one-shot. When processing
paper (and I do it manually in trays), I dump it when I am done or in 4
hours, whichever happens first.

This may be wasteful, but I need not worry about exhausting it at the rate
I make prints.

I never keep HCA past a single session, and I believe Kodak states
no longer than 24 hours. The capacity is enormous: about 14000
square inches per working gallon.

Richard Knoppow wrote:

"Tom Phillips" wrote in message
...
Greetings everyone:

So, I'm back in my darkroom after a long summer and
decided
to use up some old chems. Things are generally long-lived
in
my basememt and I've got some 5 gal. packages of KHCA.
These
are old -- possibly 5 - 10 years.

The general 'is it good v. bad' is the color of the
powder,
though I've never actually seen sulfite turn brown. The
oldest
looking package was still a sugar white. Some have said if
it
has a sulfur dioxide smell it's bad Anyway no smell and
mixed
to a clear liquid.

I've got a lot of this stuff and I could do some HT-2
tests (fix,
hypoclear, short wash, test for fixer residue) to assess
the
efficaciousness of the old hypoclear+wash but was
wondering
(richard or anyone else...) is there any chemically viable
known method to test the HCA solution directly.

TIA Tom Phillips

The principal ingredient in KHCA is Sodium sulfite. When
it is oxidezed sulfite become sulfate. Sodium sulfate does
no harm but is not nearly as effective as a wash aid as is
sulfite. The chemical does not change color when oxidized.
The brown in developers is an oxidation product of either
the Metol or Hydroquinone, since wash aid contains neither
it does not turn color.
I am not a chemist so I don't know what the test is for
sulfite nor if the presence of the metabisulfite, the other
key ingredient, would affect it. Probably the easiest test
is a wash test. Film should wash out in about five minutes
when treated in KHCA and in about 30 minutes when not
treated (hardening fixer). A sulfide test will tell if the
KHCA is working.

Richard -- do you mean an HT-2 test? The only formula I have
for a sulfide test is ST-1 for testing for adequate fixing.

The stuff does not have a long life when
mixed but unless the Kodak bags are damaged it should have a
shelf life of at least two years.
I agree about the Sulfur dioxide odor, it would indicate
decomposition of the sulfite but not oxidation, so it could
be odor free and still not effective.
Sorry I can't do better but perhaps there is a genuine
chemist following this group who can give a method of
analysing the stuff.

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

"Nicholas O. Lindan" wrote:

"Richard Knoppow"

The principal ingredient in KHCA is Sodium sulfite. When
it is oxidezed sulfite become sulfate. Sodium sulfate does
no harm but is not nearly as effective as a wash aid as is
sulfite. The chemical does not change color when oxidized.

I believe NaSO3 - NaSO4 only takes place in the presence of
water. If the powder is dry then it should be OK.

Are you saying the powdered form does not then oxidize?

The pH of a sulfite solution should drop as it oxidizes to
sulfate. I do not know what the pH values would be.
pH paper may be sensitive enough to pick up the change.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Tom Phillips wrote

Don't have permanganate, however. Unfortunately I chose not to get
it with a recent order at formulary...

I never keep HCA past a single session, and I believe Kodak states
no longer than 24 hours. The capacity is enormous: about 14000
square inches per working gallon.


To order from the Formulary you'll need to some paper work.
Permanganate is a restricted substance. The least little bit
of it will go a long way.
I've played with it a bit. It can be used to test wash water
for minute amounts of hypo. Dan