[pure-silver] Re: Yellow edges

----- Original Message ----- 
From: "Ray Rogers" <earthsoda@xxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, May 26, 2005 12:13 AM
Subject: [pure-silver] Re: Yellow edges


>
> --- Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
>
> Old handbooks often give very long times for fixing,
> on the order of 15 or 20 minutes for both film and
> paper. I think there are two reasons for
> this.
>
> One was to try to insure complete fixing where
> slopping processing practice was used.
>
> The other reason is perhaps more obscure:
>> it is to insure complete _hardening_.
>
> Richard,
> I think it might be possible that at least in some
> cases, thicker gelatin layers and or higher iodide
> content may have played some part in this.
>
> The first PRINT FILM I made required greater than what
> we now call normal fixing times. There are several
> factors involved and without knowing certain parameter
> details, I don't think it is really possible to state
> authoratitatively which factors were the main ones at
> work.
>
> Ray
>
>
  Looking at a 1947 edition of the _Kodak Reference 
Handbook_ the suggested fixing time for paper is 5 to 10 
minutes with a recommendation for two bath fixing with 5 
minutes in each bath. This is about what the current 
recommendation is.  For film fixing times are given only for 
some sheet films and for Microfile film, all suggest 10 to 
20 minutes, the latter being about right for rather 
exhausted fixer. Similar times are given in the _Processing 
and Formulas_ booklet. My memory was of longer times so I 
must at least somewhat retract my statement.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 

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