[pure-silver] Re: Microphen and possible formulas
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sat, 12 Feb 2005 02:54:28 -0800
----- Original Message -----
From: "Ryuji Suzuki" <rs@xxxxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, February 11, 2005 10:57 PM
Subject: [pure-silver] Re: Microphen and possible formulas
> From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
> Subject: [pure-silver] Re: Microphen and possible formulas
> Date: Fri, 11 Feb 2005 22:01:51 -0800
>
>> >> As far as I know they are different developers.
>> >> Microphen is
>> >> said to be same as an unnumbered Ilfored formula
>> >> developed for
>> >> repenished deep tank use.
>
> I asked Bill Troop if he has any more info on this. He
> said that
> Dignan and others assumed that Ilford Replenishing
> Developer was
> Microphen, and there is not a lot to add to this. He knows
> of no
> formula published for Microphen.
>
> Based on the comparison of the formulae, I think ID-68 is
> less likely
> to be Microphen, or more different from Microphen, but
> that doesn't
> mean IRD is Microphen.
>
>> I think it would be useful to test all three
>> developers
>> but my guess is that there probably isn't a whole lot of
>> difference.
>
> I think there is no use to even mention which is what
> formula type of
> stuff. End users should test what they use on their own
> and if
> something works that is it.
>
>> I think the pH in all of these is too low for
>> Hydroquinone to be
>> active as a developing agent as is the case with D-76.
>
> This is not true. Hydroquinone is active in this kind of
> superadditive
> developers. Same in D-76.
>
> --
> Ryuji Suzuki
> "Keep a good head and always carry a light camera."
Hydroquinone is peculiar in D-76. If the Metol is left out
very little development takes place. If the Hydroquinone is
left development is nearly as full as with it. Evidently,
the regenerative action of Hydroquinone is not affected in
the same way by pH is activity. Carlton and Crabtree tried
both combinations and show the density resulting by both
combinations. Where the Metol was left out the density was
just detectable.
The MSDS for Microphen shows two ingredients not in the
ID-68 formula. One is Sodium Tripolyphosphate, which I
believe is a sequestering agent, the other is Potassium
Metabilsufite.
I wonder if the Metabilulfite is for the purposes of
adjusting the pH in compensation for the Tripolyphosphate.
Since the MSDS gives the quantity of all ingredients save
the sulfite as 0 to 1% its not very useful (read useless)
for determining the proportions. Microphen is certainly
similar to ID-68 but I suspect that without some friendly
spy at Ilford or an analytical chemist with time on his/her
hands, there is no way to know for certain. Ryuji's
suggestion about trying both and comparing results seems a
lot simpler procedure.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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