[pure-silver] Re: 'Ripening' procedure for developer?
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sat, 5 May 2007 11:49:20 -0700
----- Original Message -----
From: "hksvk" <hksvk@xxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Saturday, May 05, 2007 6:22 AM
Subject: [pure-silver] Re: 'Ripening' procedure for
developer?
Thanks to all of you who have responded generously to this
thread. Now,
trying to twist it back to the original question:
Suppose a standard published hydroquinone/metol film or
paper developer is
built from its chemical constituents (not from powder in a
sealed package)
and brought to 68 or 70 degrees F. in a cold water bath
within 30 to 60
minutes.
Suppose a second identical mixture is allowed to sit in a
pyrex flask
overnight, covered with a watchglass, comes to the same
(ambient) temp on
its own, and is considered to be 'ripened' after 12-18
hours.
Questions: Will these two solutions have different
chemical properties? Will
film or paper respond differently to these two solutions
in any significant
perceptible way?
Thanks,
Harry.
I think this can be answered only by experiment. One
problem with poweders is that they may not dissolve
completely right away. I use mostly packaged chemicals and
have found them to work properly as soon as they have cooled
down to working temperature, often only a couple of hours.
A suggestion made in older Kodak formula books is to
dissolve the individual chemicals in small amounts of water
and then adding the liquids to the bulk of the water. This
is suggested mostly for making up large amounts of
solutions, for instance for motion picture processng, but is
also suggested for certain types of solutions even when only
small amounts are being made up.
The order of mixing can be important, as has been
pointed out in previous replys to the original question. For
instance, Metol does not dissolve easily in high
concentrations of sulfite so should be dissolved first, some
chemicals dissolve more easily at relatively high pH so
should be dissolved after the alkali.
I also suggest boiling the water to be used for a few
minutes and letting it stand and cool. This has three
effects: it drives off most dissolved gasses, it remmoves
some hardness (this is why teakettles develop a crust), it
coagulates any organic material which will then precipitate
while the boiled water sits cooling. Distilled water can
still have air dissolved in it so even that benefits from
boiling.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
=============================================================================================================
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:
