From: julian smart (julian@jsmart.fslife.co.uk)
Date: 08/21/02-04:17:37 PM Z
Sandy, Don,
I have read of many people mixing the three solutions together and getting
good results. In fact this was the way I first approached my VDB printing
sessions. I soon found ,usually the next night, that I could not get
anywhere near the result I got when the mix was fresh. I should note that
my mix was, and still is, identical to that used by Don (mentioned in his
previous posting). I mix all my chemicals in subdued (tungsten) lighting
using purified water-medicinal grade at purchase. I also leave a 24hr period
between mixing a new batch of chemicals and any printing.
When I first started, and was mixing the three sols., together I could get a
very good result on the first printing (ie 24hrs after the chemicals were
made up) but any attempt to repeat print the next night would give me a
very flat and unuseable result. Keeping the three solutions seperate (mixing
the tart. acid daily) let me print until the stocks were exhausted.
One thing that did interest me about the prievious postings was the mention
of a precipitate forming upon addition of the Silver Nitrate. I almost
always got this when using distilled water (sold as auto battery top-up),
but never get it using the purified version from pharmacies. It always used
to mix in to leave a clear solution with either water type but was
definitely worse with the distilled water. I suspect many commercially used
water distilling appliances actually are just water softeners using NaCl as
the softening agent and we, the consumers are being taken for a ride...oops
there goes my paranoia again.
Julian.
----- Original Message -----
From: "Sandy King" <sanking@clemson.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, August 21, 2002 10:25 PM
Subject: Re: Van Dyke Brown Mixing question
> Julian wrote:
>
>
>
>
> >Hi,
> > one thing I have noticed when doing a batch of VDB prints, is that if I
mix
> >all three solutions together to make a single working solution it just
> >doesn't last. It seems to go off (oxidise?) and makes producing a decent
> >print impossible even the next day.
> >I tracked the problem down to the tartaric acid, having found that the
other
> >two solutions will keep well for months in dark brown bottles. The
tartaric
> >acid solution will not work even the next day. I figure the cost of the
> >tartaric acid to be almost negligible and therefore mix this fresh before
> >any printing batch- a bit of a pain, but I always get a decent result.
> >
> >The f.A.citrate, btw , will always generate a certain amount of sludge on
> >storage. I have found this to be harmless to my prints as long as it is
not
> >disturbed in the bottom of the bottle..
> >
> >All the best,
> >
> >Julian.
>
>
> Very curious. I have not found that the combined solution goes bad,
> even after many months. Just a few days ago I finished a large bottle
> of the combined A, B, and C solution that was mixed in January or
> February of this year and the results at the end seemed as good as
> what I saw at the beginning of the year.
>
> Sandy King
> >
> >
> >----- Original Message -----
> >From: "Don Bryant" <dsbryant@mindspring.com>
> >To: <alt-photo-process-l@sask.usask.ca>
> >Sent: Wednesday, August 21, 2002 12:15 PM
> >Subject: Re: Van Dyke Brown Mixing question
> >
> >
> >> ----- Original Message -----
> >>
> >> >
> >> > Don:
> >> >
> >> > I went through this same problem with the list a few months ago, and
> >> > subsequently have mixed in part C very slowly as per the advice I
> >> received.
> >> > The batch I made last Sunday was pretty much clear by Monday
evening,
> >with
> >> > just a little sludge. Yours will probably be fine tomorrow.
> >> >
> >>
> >> Thanks Clay, I'll keep an eye on it.
> >>
> >> Don Bryant
> >>
> >>
> >>
>
>
> --
>
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