[pure-silver] Re: Thiourea and Thiourea dioxide
- From: <C.Breukel@xxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 24 Feb 2011 15:27:45 +0100
Hi Eric,
Below some quotes on FSA toner from an article by Tony McLean
In my opinion it's best to use the toner single shot:
(ps try to get the correct FSA)
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Prints rehalogenized in the iodide
bleach will reverse in tone and the borders and highlights will stain a
brown colour. Do not be concerned, the staining will clear immediately on
immersion in the FSA solution. However, I would recommend that a separate
FSA solution for prints bleached back in iodide, as residual iodide in the
FSA solution can lead to density loss in subsequent prints.
Iodine bleach with FSA
The iodine stain from the bleach will disappear on immersion into the FSA.
However, it is probably best to wash the print for 10 minutes in order to
remove the majority of the iodine. The shadow tones will then appear as a
bright yellow (silver iodide) and will gradually turn pink, then red over a
period of about 15 minutes. The re-development after an iodine bleach is
much slower than either of the other two bleaches, just the thing for Lith
printers taking a Sabbatical! It may take an hour or two to fully develop.
Although silver iodide is light sensitive, it is much less so when
'imprisoned' in its gelatin matrix, and I have not found any deterioration
in the colours of prints made this way ....as yet. There is a substantial
loss of highlight detail if the print redevelopment is curtailed at the
yellow, silver iodide stage. It would therefore be advisable to adjust the
contrast of the original print to compensate.
________________________________________
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Eric Nelson
Sent: donderdag 24 februari 2011 15:15
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Thiourea and Thiourea dioxide
I used the iodide version as I had the chemicals for that; I don't have
sulphuric for the other bleach. Using the iodide bleach once you see the image
starting to lighten, it's pretty much time to pull the print as the toner
doesn't add density in my case and perhaps it was because I was using RC paper.
Also the tip in Tim's book of re-bleaching (if I don't like the results of the
toner) and then putting back into a developer (assuming dektol etc was meant)
didn't work here either.
Of course looking at the chemical formula for TD vs my thiourea I see that they
look very different so thhat may explain a lot, but what that means chemically
I have no idea.
Eric
________________________________________
From: "C.Breukel@xxxxxxx" <C.Breukel@xxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Thu, February 24, 2011 7:30:34 AM
Subject: [pure-silver] Re: Thiourea and Thiourea dioxide
Hi Eric,
I am surprised here: FSA is my favorite toner. I use it mostly on partially
toned prints, because the density gain is considerable (your image can get 1-1
½ stops darker on a completely bleached print, depending on the paper). I like
the flexibility of the different bleaches.
Redevelopment (FSA is not really a toner, see Tim's book) in FSA is generally
very fast: 30 sec-1 min., exception is after the Iodine bleach, than
re-development takes a lot of time (by heart: 30 minutes or so)
Good luck,
Cor
Btw my FSA http://tinyurl.com/669jflo
Good luck,
Cor
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