[pure-silver] Re: Emulsion hardening for reversal processing of 35mm B&W film
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: "Pure-Silver Free" <pure-silver@xxxxxxxxxxxxx>
- Date: Sun, 31 Oct 2004 14:46:55 -0800
----- Original Message -----
From: "Nick Zentena" <zentena@xxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Sunday, October 31, 2004 8:20 AM
Subject: [pure-silver] Re: Emulsion hardening for reversal
processing of 35mm B&W film
> On October 31, 2004 08:58 am, Jordan Wosnick wrote:
>
>> and 'slimy' (for lack of a better term) during the
>> processing and
>> makes for damaged images.
>
> I think slime means alkaline.
>
>> bleaching?) And suggestions for an easy-to-mix hardening
>> solution? I do have some E6 stabilizer on hand here at
>> home,
>> which I believe has some hardening functions.
>
>
> I think E-6 stabilizer is similar to C-41 stabilizer.
> Basically
> water,photo-flo and formaldehyde. The Formaldehyde
> slows/stops fading but
> it's not a hardner.
>
> Maybe a different bleach if you think that's the issue?
> Which formula are you
> using for this?
>
> Nick
Formaldehyde is a VERY effective hardener. It is used in
emulsion making and as a pre treatment for very alkaline
processes that soften emulsions. An example of an auxillary
hardener is:
Kodak SH-1 Supplenentary Hardener
Water 500.0 ml
Formalin* 10.0 ml
Sodium Carbonate, dessicated 5.0 grams
Water to make 1.0 liter
*Formalin is a 40% Formaldehyde solution
If monohydrated carbonate is used the amount is 5.9 grams.
The negative should be treated in this solution for 3
minutes. The rinsed and treated in fresh acid fixer for 5
minutes, then washed.
I don't know the function of the final fixing step.
Formaldehyde maintains hardness in highly alkaline
solutions which destroy the hardening action of metallic
hardeners like white alum and chrome alum.
Its likely the color stabilizer would serve the purpose.
A more modern oganic hardener is Glutaraldehyde. This can
be added directly to developers. It is added, for instance,
to some of Grant Haist's monobath processes.
T-Max films have much harder emulsions than most other
B&W film. It is possible that some of the gelatin is
replaced by a synthetic as in color films.
What reversal formulas are you using?
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you subscribed,)
and unsubscribe from there.
Other related posts:
