[alt-photo] Re: The Illusive Black Cyanotype - Any Insight?

[Don Sweet]

I've been lurking here waiting for somebody to start channelling Judy

Don Sweet

----- Original Message ----- 
From: "Paul Viapiano" <viapiano at pacbell.net>
To: "The alternative photographic processes mailing list"
<alt-photo-process-list at lists.altphotolist.org>
Sent: Thursday, September 22, 2011 1:52 PM
Subject: [alt-photo] Re: The Illusive Black Cyanotype - Any Insight?


> Elusive, not illusive  ;-)
>
>
>
> ----- Original Message ----- 
> From: "Ryuji Suzuki" <rs at silvergrain.org>
> To: "The alternative photographic processes mailing list"
> <alt-photo-process-list at lists.altphotolist.org>
> Sent: Wednesday, September 21, 2011 1:59 PM
> Subject: [alt-photo] Re: The Illusive Black Cyanotype - Any Insight?
>
>
> >I doubt salicylic acid would tone prussian blue pigment. The iron in the
> >blue pigment is tightly bound to cyano ligands and salicylic acid is way
> >too weak to undo that.
> >
> > Salicylic acid was useful in poisoning the redox catalyst activity of
free
> > ferrous/ferric ions in ascorbate developers, but that was a very
different
> > aim. Even then, I wouldn't be surprised if there were multiple
mechanisms
> > involved (e.g., free radical scavenging actions) as I don't think
> > iron-salicylate complex is very stable in alkaline solutions.
> >
> > In the protocol you described, nitric acid is probably used to decompose
> > prussian blue to free up iron for further reactions. But you don't want
> > the image to become blurry (and lose density) by allowing the iron to
> > freely diffuse in the material, so carbonate solution is used in
between.
> > But Mike Ware is the expert to ask on this topic.
> >
> > If the objective is to convert prussian blue pigment to brown black,
> > another way to do it would be to use a weak solution of sodium sulfide
or
> > ammonium sulfide (pH around 6).
> >
> > -- 
> > Ryuji Suzuki
> > "Don't play what's there, play what's not there." (Miles Davis)
> >
> >
> >
> >
> > Gordon Holtslander wrote:
> >> Ryuji Suzuki uses salicylic acid in some of his developers to sequester
> >> iron.
> >> http://www.digitaltruth.com/data/ds-10.php
> >>
> >> I wonder if a salicylic acid could be used to clear iron  in toning
> >> cyanotype?
> >>
> >> Salicylic acid is a phenolic acid like tannic acid.  It may tone
> >> cyanotypes as well.
> >>
> >> Gord
> >>
> >>
> >> ----- Original Message -----
> >> From: Francesco Fragomeni<fdfragomeni at gmail.com>
> >> Date: Tuesday, September 20, 2011 4:07 pm
> >> Subject: [alt-photo] Re: The Illusive Black Cyanotype - Any Insight?
> >> To: The alternative photographic processes mailing
> >> list<alt-photo-process-list at lists.altphotolist.org>
> >>
> >>> In regard to the gallic acid toning procedure, can anyone
> >>> confirm what the
> >>> nitric acid does? My assumption is that it is a clearing agent
> >>> intended to
> >>> aggressively neutralize or remove excess iron residue before
> >>> bleaching in
> >>> sodium carbonate and then toning in the gallic acid. Can anyone
> >>> confirmthis?
> >>>
> >>> -Francesco
> >
> >
> >
> >>>>>> On Mon, Sep 19, 2011 at 9:05 PM, Gordon J. Holtslander
> >>> <gjh at shaw.ca>>>  wrote:
> >>>>>>> Have you tried this:
> >>>>>>>
> >>>>>>> To convert Cyano to black tones:
> >>>>>>> Place print in solution of 3 drops Nitric Acid added to 1
> >>> litre water
> >>>>> for
> >>>>>>> two minutes transfer to bath of 14g Sodium Carbonate +
> >>> 160cc water -
> >>>>> leave
> >>>>>>> till image disappears and then reappears with an orange
> >>> tone transfer
> >>>>> print
> >>>>>>> to third solution of 14g Gallic Acid + 160cc water - black
> >>> tones will
> >>>>> appear
> >>>>>>> wash 30 min.
> >>>>>>>
> >>>>>>> perhaps the ferrogallic process would work;
> >>>>>>> (from Photographic Facts and Formulas 1940)
> >>>>>>>
> >>>>>>> ferric
> >>> chloride         50g
> >>>>>>> ferric suplphate
> >>> (basic)        25g
> >>>>>>> tartaric
> >>> acid                   45g
> >>> water                           500 ml
> >>>>>>> Dissolve and add
> >>>>>>>
> >>>>>>>
> >>> gelatin                         25g
> >>> water                           250cc
> >>>>>>> soak gelatin for 30 minutes and dissolve
> >>>>>>>
> >>>>>>> Development details are not given though
> >>>>>>>
> >>>>>>> Gord
> > _______________________________________________
> > Alt-photo-process-list | http://altphotolist.org/listinfo
>
> _______________________________________________
> Alt-photo-process-list | http://altphotolist.org/listinfo