[pure-silver] Re: Adding Pot Bromife to PC-TEA
- From: "Koch, Gerald" <gkoch02@xxxxxxxxxx>
- To: "'pure-silver@xxxxxxxxxxxxx'" <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 6 Jan 2005 17:29:04 -0500
I never measured the temperature. I will do that when I make another batch
(which may be awhile). I think Gainer stated in either his article in
PhotoTechniques or in a post on the net that the ascorbic acid would eventually
go into solution without heating after a few days.
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx]
On Behalf Of John Black
Sent: Thursday, January 06, 2005 5:18 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Adding Pot Bromife to PC-TEA
> I worried about this too. The solution does darken but still works.
I think the darkening is mostly due to the phenidone because my developer
concentrates using Dimezone-S don't show it nearly as bad. The color increaes
with time but doesn't seem to be related to loss of activity.
>
> I have found that you don't have to heat the solvent as hot as Gainer
suggests.
That would be very good news. When I make my Meoh PC solutions, I have to
gently heat up the alcohol to disolve the ascorbic acid. I usually run hot
water from the tap into a bucket and put the methanol bottle in it with the
VitC. When it comes up to hot water temp, the ascorbic acid goes right in. I
might try that with the glycols. I refuse to use TEA again as a solvent. I've
had more fun with Karo syrup.
> I put the TEA or glycol in a beaker and add the ascorbic acid. I
> start
heating
> the contents in the microwave in 10-15 sec intervals. I stir the
> solution
after
> each heating to see if all the solid will dissolve. When it finally
> does
I then
> add the Phenidone or Dimezone-S. This way the solution does not get
overheated.
What is the lowest temp you find that will disolve the vitamine C? Gainer
called for 9gm per 100ml but neglected to tell that no more than that will go
into solution. More can be disolved in hot solvent but some will precipitate
when it cools.
>
> The bromide is another matter since it is an ionic solid and should
> not be soluble in non-ionic solvents. In fact I did not consider its
<bromide snip>
So far, if I keep the pH ruthlessly around 8.3 I don't need any bromide (for
film). Paper developer at pH 10 or above is a different matter though.
JB
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