[rollei_list] Re: OT: development
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Fri, 20 May 2005 20:56:59 -0700
----- Original Message -----
From: "Allen Zak" <azak@xxxxxxxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Friday, May 20, 2005 8:36 PM
Subject: [rollei_list] Re: OT: development
> In 50 years of photography I have not once experienced
> emulsion damage
> from using non-hardening fixers.
>
> Allen Zak
>
I doubt if many if any current materials need hardener.
The standard hardening fixing baths like Kodak F-5
(essentially the packaged Kodak fixer) originated in the
mid-1930s when emulsions were very soft compared to modern
materials. In fact, up to about 1939 the standard processing
temperature was 65F. It was raised to 68F after that because
some method of improving hardening was applied. I think we
use hardening fixer mostly because of tradition.
Auxilliary hardener is included in some color processes
which operate at very high temperatures and are necessary
for some special processes like monobaths, which are very
high in pH, but I agree that in general one could do without
hardener and suffer no consequences.
OTOH, if a wash aid is used the hardener does no harm and
may cause film to dry faster (less absorbed moisture due to
less swelling).
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
---
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