[pure-silver] Re: Ansco 221 Observations & Questions

This is the link to the Defender formulas plus info on toning.
http://silvergrain.org/wiki/Toning

Jonathan Ayers [mail1@xxxxxxxxxxxxxxxxx]

-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow
Sent: Saturday, June 09, 2007 7:54 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Ansco 221 Observations & Questions


----- Original Message ----- 
From: "Tim Rudman" <tim@xxxxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Saturday, June 09, 2007 6:30 AM
Subject: [pure-silver] Re: Ansco 221 Observations & 
Questions


> Hi Eric
> Re your question to Richard;
> "When you say "completely bleach the image" do you mean 
> there shouldn't be
> any image left?  Typically deep blacks here remain quite 
> visible after
> bleaching.
> Eric "
> Take a look at my post just before yours. You may either 
> bleach the blacks
> completely, or leave some, depending on the result you are 
> after.
> Some papers (notably cold tone ones) are very slow to 
> loose the last blacks,
> but they will (IME) if the bleaching stage is strong 
> enough and long enough.
> Best wishes
> Tim
> http://www.worldoflithprinting.com

   I think Tim answered your queston in his other post. Here 
are a couple of thoughts which might make things clearer. 
The toner works by treating the image in a bleach that 
converts the metallic silver image back to a silver halide. 
Ansco 221 and most other Sepia toners convert it to Silver 
Bromide by having some postassium bromide in the bleach but 
other bleaches exist that convert the silver to Silver 
Chloride or even Iodide. The second step is to treat the 
bleached image in a substance that converts it to Silver 
Sulfide. This can be either Sodium Sulfide or Thiourea. The 
latter has the advantage of being odorless while the Sulfide 
emmits Hydrogen Sulfide which gives it the rotten egg odor. 
The sulfide will convert all halide to silver sulfide but 
doesn't do much to metallic silver. If the image is partly 
bleached the metallic silver in the unbleached part is not 
toned. This is useful if a split tone is desired. If the 
print is not subsequently toned in another toner the effect 
is simply to leave the shadow areas darker and colder than 
the rest of the image. The drawback is that the protection 
against image degradation is not complete in the untoned 
areas. A subsequent toner can be used to get a split Sepia 
tone or to get a special effect. For instance, if a Gold 
toner is used after Sepia toning the toned areas will be 
turned red. Areas left unbleached will be toned blue 
although it may not a very vivid blue. Since Gold is also a 
very good protectant such a split toned print will be quite 
permanent.
    Many years ago Defender Photo (which was later to become 
part of Dupont) published a set of Sepia toner forumae for 
use on its Varigam paper. There were three bleach variations 
and three toner variations, all using Thiocarbamide. By 
combining them one could get a variety of tones from cold 
brown to yellow. I've posted these to this list in the past 
and to the rec.photo.darkroom news group. The latter 
probably can be found by using Google groups search. The 
colors given by this toner were for the long discontinued 
Varigam but that was a neutral tone paper similar to many VC 
papers on the market now so the general range of colors 
should be similar.
    The effectiveness of the bleach depends on its strength 
and other constituents. Older types of graded papers were 
usually some mixture of Silver bromide and Silver Chloride 
although some were completely one or the other halide. 
Modern papers also contain some Silver Iodide, formerly 
found only in film emulsions. I suspect this is one reason 
they may be harder to bleach. I have not tried the formulas 
for sepia toning lantern slide or motion picture film on 
modern paper but suspect they would work. The bleach 
formulas appear to be stronger than those for paper.
    The old instructions for indirect toners usually specify 
bleaching until the image has turned entirely yellow or 
cream colored. The older papers would bleach in maybe two to 
five minutes. I've let modern paper soak in Kodak toner 
bleach for ten minutes without getting this degree of 
bleaching but remember when I first tried a sepia toner, 
perhaps fifty years ago, it worked as the old instructions 
would lead you to expect.


---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 

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