arkins@banet.net
Sun, 23 May 1999 12:36:10 -0400
Is the FX-2 formula in the Film Development Cookbook a concentrate? I
thought it was a working solution. Also, I don't believe any developing
times were given in that book for FX2 with Tri-X or T-Max 400. Does anyone
have any suggestions?
-----Original Message-----
From: Richard Knoppow <dickburk@ix.netcom.com>
To: alt-photo-process-l@sask.usask.ca <alt-photo-process-l@sask.usask.ca>
Date: Sunday, May 23, 1999 3:59 AM
Subject: Re: Question about FX-2
>At 03:30 PM 5/21/99 -0500, you wrote:
>>Does any one on the list use Crawley FX-2 developer? If so I would
>>appreciate your comments about its qualities.
>>
>>In The Film Developer Cookbook the directions to mix FX-2 call for the use
>>of potassium carbonate crystals, not anhydrous (the crystal form is said
to
>>give a slight bicarbonate buffer effect). What does this mean, and how
>>might the same effect be gotten with the anhydrous variety?
>>
>>Sandy King
>>
> The original FX-2 formula is for a highly concentrated stock solution and
>I think the preference for both the Potassium salt and the crystaline form
>stem from their greater soluability.
> In a developer the carbonate slowly hydrolizes to produce both the
>hydroxide, which is the actual accellerator, and bicarbonate. Because of
>the large resevoir of hydroxide in the carbonate it act as a good buffer
>and the pH of the solution tends to remain constant
> Sodium carbonate is usually preferred over the potassium salt because it
>is not delequescent. Potassium carbonate is very delequescent so must be
>stored very carefully to prevent moisture absorption and consequent loss of
>strength.
> Again it is this very quality which makes potassium crystals desirable
>for highly concentrated developers like FX-2.
>----
>Richard Knoppow
>Los Angeles,Ca.
>dickburk@ix.netcom.com
>
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:39:35