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Photo Forum / Film Photography / Film and Labs / August 2005

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D-76 and Boric Anhydride.

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Keith Tapscott - 27 Dec 2004 18:13 GMT
Thanks to the Analyst for replying to my question of Boric Anhydride in
D-76. However, if Kodak state that a certain chemical component is included
in a specific processing product in their MSDS then I have no reason to
doubt their word, after all why should such a reputable company deliberately
mislead their customers?
To go back to my original question, I was asking what the function of Boric
Acid has in D-76 and how does it differ from Boric Acid?
Now here is another question, if you think that the commercially packaged
Kodak developer is the D-76d formula, then why does the Kodak product
contain close to 110 grams of constituents per litre instead of 123 grams
that are in the D-76d formula?
Kodak are hardly going to reveal a company secret and I certainly don't
expect them to. I was simply asking about the function of Boric Anhydride in
Kodak D-76 and how does it differ to Boric Acid?
Does anybody out there actually know the answer besides a Kodak chemist?
the analyst - 28 Dec 2004 01:54 GMT
*Thanks to the Analyst for replying to my question of Boric Anhydride in
*D-76. However, if Kodak state that a certain chemical component is included
*in a specific processing product in their MSDS then I have no reason to
*doubt their word, after all why should such a reputable company deliberately
*mislead their customers?

you wouldn't see the difference regardless of which components were
used. In solution most compounds exist in ionised form. Anhydride
means "less water". When you remove water from boric acid, you get
anhydride, or as we call it boric oxide. In my view, Kodak put boric
anhydride as a generic term for boric acid and borates.
I deal with MSDS on daily basis, and can assure you, thsoe documents
are worthless for chemists, we can make our own assessment. Laypeople
wouldn't have a clue to verify, if the MSDS is right or not.
Going back to your example of D76 - it has to be pH 9 or around to
work. Boric oxide will lower pH, hence some carbonate or hydroxide
needs to be added to compensate. from manufacturing point of view, it
does not make sense. Boraks is not hygroscopic like anhydride, it is
cheap.
If you believe Kodak is a reputable company, then good luck.

*To go back to my original question, I was asking what the function of Boric
*Acid has in D-76 and how does it differ from Boric Acid?

Some modified D76 formulations use a mixture of boraks and boric acid.
Such develeoper has slightly lower pH, it is less active, but also
exhibit less changes when developer is reused (better buffering).

*Now here is another question, if you think that the commercially packaged
*Kodak developer is the D-76d formula, then why does the Kodak product
*contain close to 110 grams of constituents per litre instead of 123 grams
*that are in the D-76d formula?

You assume anhydrous salts, which may not be the case. i cannot answer
for Kodak, the only way would be to analyse it. Compare dev times, do
they match D76 or D76d? In my view, commercial D76 from Kodak equates
D76 from formulae. Kodak put boraks into bags, not boric oxide, end of
story. If you believe otherwise, sorry i cannot help.

*Kodak are hardly going to reveal a company secret and I certainly don't
*expect them to.

That secret is no secret for over 70 years.

* I was simply asking about the function of Boric Anhydride in
*Kodak D-76 and how does it differ to Boric Acid?

There is no boric anhydride in Kodak D76.
In solution boric anhydride react with water forming boric acid.
For all practical purposes, they would be equivalent.

*Does anybody out there actually know the answer besides a Kodak chemist?
Any chemist understanding inorganic chemistry.
Ilford, Agfa, and many other independent manufacturers.

Stop treating MSDS like Bible or any other holly book.
*
filmdesigner69@yahoo.com - 28 Dec 2004 04:42 GMT
> *Does anybody out there actually know the answer besides a Kodak chemist?
> Any chemist understanding inorganic chemistry.
> Ilford, Agfa, and many other independent manufacturers.
*

But anyone who repeatedly mispells "borax" probably isn't a chemist.
the analyst - 28 Dec 2004 08:29 GMT
well, being multilingual, I often misspell names. It is correct in one
of them. I am a chemist for many years.

*the analyst wrote:
*
*> *Does anybody out there actually know the answer besides a Kodak
*chemist?
*> Any chemist understanding inorganic chemistry.
*> Ilford, Agfa, and many other independent manufacturers.
**
*
*But anyone who repeatedly mispells "borax" probably isn't a chemist.
filmdesigner69@yahoo.com - 28 Dec 2004 13:45 GMT
> To go back to my original question, I was asking what the function of Boric
> Acid has in D-76 and how does it differ from Boric Acid?

Borate in one form or another is used in B&W developers to buffer pH
between 8.5 and 10.
the analyst - 28 Dec 2004 21:54 GMT
I've checked MSDS for D-76 (not Kodak)
It appears that it does NOT match published formulae.
It probably has less than 100 g of sulfite, and a small quantity of
boric acid (listed as boric anhydride=boric oxide).
I would not be surprised, if there is a bit of KBr as well (say 0.3g).
Balancing borate/boric acid will give more stable pH (less difference
between the new and used dev), small KBr content would season the
developer, so there is less change in fog between an unused and used
dev.
Agfa and Fuji followed that path.
*
*Keith Tapscott wrote:
*
*> To go back to my original question, I was asking what the function of
*Boric
*> Acid has in D-76 and how does it differ from Boric Acid?
*
*Borate in one form or another is used in B&W developers to buffer pH
*between 8.5 and 10.
Keith. Tapscott. - 15 Aug 2005 20:35 GMT
>I've checked MSDS for D-76 (not Kodak)
>It appears that it does NOT match published formulae.
[quoted text clipped - 15 lines]
>*Borate in one form or another is used in B&W developers to buffer pH
>*between 8.5 and 10.

I had forgotten about this thread that I started last December, if the
Analyst is still out there some where, I`d like to say a very, belated thank
you for your contribution.
uraniumcommittee@yahoo.com - 29 Dec 2004 03:54 GMT
None of this matters. Kodak produces a consumer version of D-76 which
is better than the original formula rom the standpoint of consistency
and reliability. That's all you have to know.
the analyst - 29 Dec 2004 10:17 GMT
thanks for indicating, what is good for me. Although, I dare to
differ. my understanding is that people in this group want to know
more than manufacturers would like them to know. I would say, we want
to know and we want to decide, what to do in certain situation. It is
part of fun.

*None of this matters. Kodak produces a consumer version of D-76 which
*is better than the original formula rom the standpoint of consistency
*and reliability. That's all you have to know.
uraniumcommittee@yahoo.com - 29 Dec 2004 18:04 GMT
D-76 by the original formula is unbuffered. It can shift ph under some
circumstances, which causes problems with consistency. The buffered
version sold by Kodak is photographically identical for all practical
purposes, but offers protection against this problem.

Don't sweat it.

You can mix up D-76 d yourself.
See:

http://www.binbooks.com/books/photo/i/l/581A6AF553
uraniumcommittee@yahoo.com - 29 Dec 2004 18:07 GMT
D-76 by the original formula is unbuffered. It can shift ph under some
circumstances, which causes problems with consistency. The buffered
version sold by Kodak is photographically identical for all practical
purposes, but offers protection against this problem.

Don't sweat it.

You can mix up D-76 d yourself.
See:

http://www.binbooks.com/books/photo/i/l/581A6AF553
the analyst - 29 Dec 2004 21:20 GMT
*D-76 by the original formula is unbuffered.

Wrong

* It can shift ph under some
*circumstances, which causes problems with consistency.

Prepare your D76 before use, store in full bottle well closed.

*The buffered
*version sold by Kodak is photographically identical for all practical
*purposes, but offers protection against this problem.

Prove that it is identical.
*
*Don't sweat it.
*
*You can mix up D-76 d yourself.
*See:
*
*http://www.binbooks.com/books/photo/i/l/581A6AF553
 
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