[pure-silver] Re: Adding Pot Bromife to PC-TEA
- From: "John Black" <jblack@xxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 6 Jan 2005 13:01:58 -0500
> I was testing a new lens on one of my Nikons. The film was 35mm Eastman
5231
> ISO 80 rated at an EI of 125 and developed in the following developer
(diluted)
> 1+49 for 8 minutes at 22 C.
>
> Propylene glycol ....................... 50.0 ml
> Triethanolamine ........................ 50.0 ml
> Ascorbic acid .......................... 9.0 g
> Dimezone-S ............................. 0.3 g
> Potassium bromide ...................... 0.25 g
>
> Without the bromide there was an objectionable amount of fog and it was
> difficult to obtain sufficient contrast without too much density.
Hmmm.... My PC-TEA used G's recommended concentration of TEA that has twice
as much as this. I dispersed (can't really use the term dissolved) the P and
C in 100ml TEA with no PrGL. I was put off by the viscous nature of the TEA
so I thinned it out 1:1 with dry methanol. The resultant mixture I diluted
1:25 for use. Your modification cuts the TEA in half, which should be fine
as it is somewhat in excess in G's formulas.
I agree that the unmodified PC/TEA as per Gainer gives some fog but is quite
active and shows a good CI and speed. In my hands, though, it is grainier
than I would like (yes, I'm probably too anal about it) resulting from a
higher pH than I would like. If you dilute the PC/TEA in water that has 5/5
(gm/L) sulfite/boric acid, the pH come down and the fog disappears. All
this is for 35mm though, and I would not hesitate to use the unmodified
Gainer formulations for RF and LF.
BTW, my TEA is reagent grade from Sigma so it should behave normally.
JB
=============================================================================================================
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:
