[pure-silver] Re: Fixing after indirect toning - a deeper question
- From: Christopher Woodhouse <chris.woodhouse@xxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sat, 14 Jan 2006 22:12:26 +0000
Yes Tim, I was just considering Sepia. I read Richard's comments and he
recurring recommendation of using Selenium toner (after washing) to detect
undeveloped silver. Try as I might, I have never got that method to detect
anything, hence my comments about the very sensitive nature of sepia toners
to any silver salts lying about and the logical extension that it must be
hard for the sepia toner to leave any undeveloped silver behind.
On 14/1/06 09:28, "Tim Rudman" <tim@xxxxxxxxxxxxxxx> wrote:
> << Some, but not all, indirect toners leave some silver
> _halide_ behind after toning.>> (Richard)
>
> This is particularly true of many of the metal ferrocyanide toners. It has
> been estimated that only about 75% of the silver halide is converted to the
> non-silver metal with iron and copper toning. For this reason post-toning
> fixing is sometimes used after these toners to brighten the colour &/or to
> minimize colour change from sulphuration.
>
> (E.G: Quote from my Toning book: In addition to this, not all the
> image-silver is converted to ferric ferrocyanide in the toning process. A
> quarter of it is converted to the nearly colourless silver ferrocyanide and
> this is very susceptible to turning brown from sulphuration by atmospheric
> pollutants. If this is fixed away by a weak acid fix after toning, the
> colour will shift a little, but the image should be much more stable.)
>
> I wasn't sure from your post Chris, whether you were asking only about
> sepia?
>
> Tim
> http://www.worldbookoflithprinting.com
>
>
> -----Original Message-----
> From: pure-silver-bounce@xxxxxxxxxxxxx
> [mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow
> Sent: 13 January 2006 23:15
> To: pure-silver@xxxxxxxxxxxxx
> Subject: [pure-silver] Re: Fixing after indirect toning - a deeper question
>
>
> ----- Original Message -----
> From: "Christopher Woodhouse" <chris.woodhouse@xxxxxxxxxxxx>
> To: <pure-silver@xxxxxxxxxxxxx>
> Sent: Thursday, January 12, 2006 1:15 PM
> Subject: [pure-silver] Fixing after indirect toning - a deeper question
>
>
>> I have read the recommendation that fixing after indirect toning
>> removes and untoned silver from the print. Whilst I know that during
>> the toning step, there is a clear build up of image tone and colour
>> change over a few minutes, suggesting that if one pulls a print
>> early, some of the bleached silver will remain untoned. So far so
>> good.
>>
>>
>> But... Is it being suggested that longer toning, say 5
>> minutes with
>> agitation, of a bleached print still leaves behind
>> residual bleached silver?
>> In the back of my mind I know toner will quickly detect
>> incomplete fixing
>> and even show up poor washing too, discolouring the paper
>> wherever there are
>> reactive silver complexes....so why should toner at the
>> same time be so poor
>> at converting the bleached silver back into silver
>> sulphide?
>> --
>> Regards Chris Woodhouse ARPS (All Real Photos use
>> Silver)
>>
>
> Some, but not all, indirect toners leave some silver
> _halide_ behind after toning. The final fixing step is to
> remove this halide which otherwise will have the same effect
> as incompletely fixing of an untoned image. The halide will
> eventually decompose causing staining. In the case of an
> untoned image the decomposing halide will also attack the
> silver but may have less effect on the silver sulfide of a
> toned image.
> A final fixing step is absolutely required for Nelson's
> Gold Toner but probably not for hypo-alum type toners. Often
> the fixing step recommended after hypo-alum is mainly to
> harden the emulsion after exposure to the relatively high pH
> and high temperatures of the toning bath.
> Note that a fixing bath does not dissolve metallic
> silver, only silver halide (very extended fixing, especially
> in acid ammonium thiosulfate fixers _do_ remove some
> metallic silver).
> Some toners will tone halide as readily as metallic
> silver so well fixed prints are a necessity. The standard
> test for fixing is a 2% solution of Sodium Sulfide, about
> the same as the redevelopment bath of indirect Sepia toner.
> A polysulfide toner like Kodak Brown Toner will also tone
> halide resulting in a stain if the print is not well fixed.
> Of course, an indirect (bleach and redevelop) toner will do
> the same thing.
> Not all toners require extensive washing before toning.
> Hypo-Alum-Sepia toner in particular requires only a short
> rinse.
> Kodak Rapid Selenium Toner also tones halide and, in the
> past, was suggested by Kodak as an alternative to sulfide as
> a test for fixing (at 1:9 dilution). It fails where there is
> too much hypo in the emulsion so must be used only on well
> washed materials.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
>
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--
Regards Chris Woodhouse
.... __o
.. -\<,
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