[pure-silver] Re: word from ilford
- From: Eric Nelson <emanmb@xxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 15 Aug 2007 10:27:20 -0700 (PDT)
I have heard of silver prints being damaged by
environmental elements but always believed they needed
to be in the extreme to cause the degree of image
degradation that happened in my case.
I am relieved that I wasn't the cause via neglect or
what-have-you, but somewhat disillusioned in the
stability of silver after this. I will probably offer
the caveat to clients re:achival aspects of silver
prints, that selenium is advised when prints are to be
kept long term in unknown environs.
But maybe I was the cause since Richard made mention
of the need for a little fixer left behind and I just
washed too well. ;-)
Typically when I print for someone, I will give them
the "B" prints, as they will only be trash to me, and
a little good will like that goes a long way.
Sometimes I am surprised when they prefer the "B"
print.
So my client went back to her B's I had given her, and
sure enough they are fine and unaffected, pretty much
confirming the environmental damage theory.
Even better, the prints are acceptable to her as a
replacement so I don't have to re-print as I'm way too
busy to get to that for a long time right now anyway.
Re: selenium & rc; I remember back some years a lab
that specialized in only "archival rc prints" banking
on the perception or sales pitch at the time that RC
was as stable as fiber when selenium toned. They
found out later the proponents of this were wrong as
prints started to go off and they either shifted to
fiber or gave up the ghost. I think this was around
'97-'98. Pehaps this is before the Titanium Dioxide
was removed from those papers.
Eric
--- Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
>
> ----- Original Message -----
> From: "Steve Nicholls" <gl1500@xxxxxxxxxxxxxxxx>
> To: <pure-silver@xxxxxxxxxxxxx>
> Sent: Tuesday, August 14, 2007 5:38 PM
> Subject: [pure-silver] Re: word from ilford
>
>
> > Eric Nelson wrote:
> >> I got a call from Mike Bain from Ilford/Harman,
> and
> >> his opinion, as well as one other person he
> consulted,
> >> is that these prints we've been discussing have
> >> suffered oxidative bronzing.
> >> Now to me bronzing has been a defect that
> presents as
> >> a reflective mirror effect with little or no
> >> discoloration such as an over exposed albumen
> print,
> >> but Mike assured me this is different and is
> >> attributed to pollutants of one kind or another.
> >>
> >>
> > I had three RC prints do virtually the same and it
> was the
> > glues used in the mounting. Not done by me. They
> were
> > mounted under glass.
> >
> >> [snip]
> >>
> >
> >> His only suggestion to prevent this from
> happening is
> >> selenium toning for a few minutes in either 1:19
> or
> >> 1:31 dilutions.
> >>
> >> I had always thought that silver prints processed
> &
> >> washed well would be fairly archival and that
> selenium
> >> gives and added amount of stability for the truly
> >> paranoid and also cools the image, but it seems
> from
> >> this conversation that selenium is pretty much a
> >> necessary part of the silver process when sending
> off
> >> work to unknown environments and handling.
> >>
> >>
> > At the 1:31 dilution I doubt there would be any
> colour
> > change.
> > Afga Sistan is also recommend for similar reasons.
>
> > Apparently it has been re-released by AO ??
> >
> > Steve
> >
>
>
> There seems to be no research data on Sistan.
> It may
> very well work but I've never seen any proof. Fuji
> published
> a research paper on Ag-Guard, another stabilizer.
> Ag-Guard
> is different from Sistan so research on one does not
>
> necessarily apply to the other. The Fuji research
> showed
> that Ag-Guard was effective in protecting images
> against
> action by oxidizers but less so than sulfiding
> toners.
> Very dilute solutions of Kodak Rapid Selenium
> Toner do
> not tone all densities uniformly. While early
> resarch showed
> KRST to be an effective protective treatment it
> appears to
> have changed in some way about 20 years ago. After
> that
> change it was no longer effective in weak dilution.
> The
> research showing this was carried out by the Image
> Permenance Institute of the Rochester Institute of
> Technology. At stronger dilutions KRST is effective
> but will
> change the color or density or both of the image.
> The
> recommended treatment is at a dilution of not more
> than 1:9
> and for not shorter than 3 minutes at 68F.
> A better treatment is a liver of sulfur type
> toner such
> as Kodak Brown Toner. These toners convert silver
> uniformly
> regardless of grain size so partial toning will have
> some
> protective action on all densities. However, KBT
> does cause
> a color change on many materials. It, and similar
> toners,
> are now the recommended protective treatment for
> microfilm.
> Gold toners are also quite effective but are
> expensive.
> Gold toner produces a neutral to bluish image on
> neutral
> tone paper and a blue color on warm tone paper.
> Bronzing or silvering out is an effect of
> atmospheric
> oxidizers on the image. The convert the silver to a
> very
> finely devided Silver Oxide which then can migrate
> to the
> surface of the emulsion where some of it is
> converted back
> to metalllic silver by other polutants. The metallic
> silver
> can be yellow to silver in color depending on how
> finely
> devided it is. Silver oxide is black so there are
> also black
> stains on the surface of the print. These stains can
> often
> be removed but some silver will have been removed
> from the
> image so it may be faded.
> Metallic silver can also be sulfided from
> polutants in
> the air or in the emulsion. Usually, this results in
> a brown
> or yellow stain. Where there are sulfur containing
> compounds
> in the emulsion, such as hypo or fixer reaction
> products,
> the stain can be generalized, not just of the image.
> In some
> cases the stains can be removed but some techniques
> recommended in the past have been shown to
> accelerate future
> aging of the image.
> A very small residue of hypo remaining in the
> emulsion
> can act as a stabilzer by partially sulfiding the
> silver.
> This prevents further sulfiding or oxidation.
> However, other
> than not using very extended washing there is no
> recommendation and not much information is available
> about
> how much hypo should be retained. This effect has
> been known
> since about 1960. It may be one reason that some
> drugstore
> processed snapshots have survived in relatively good
>
> condition. It has been shown, however, that film and
> paper
> processed to the old standard of having no residual
> hypo is
> particularly vulnerable to oxidative attack, unless
> it has
> been toned. Sources of peroxides are plentiful
> especially in
> urban areas. For best life prints should be toned in
> a
> Liver-of Sulfur toner, a fairly strong solution of
> KRST (as
> indicated above), a Gold toner or fully toned in
> nearly any
> sulfiding toner where the resulting image color is
> not
> objectionable.
> In general, prints should not be covered by
> tightly
> fitting glass or plastic covers, especially RC
> prints.
> Note that in the past RC prints were subject to
>
> oxidation from a gas emitted by the Titanium Dioxide
>
> reflective layer beneth the emulsion. This effect
> was
> exagerated when the prints were mounted under glass
> or
> plastic, which prevented escape of the gas. This gas
>
> attacked both the image and the plastic layer
> causing it to
> craze and even flake off. Modern RC papers contain
> scavengers for these gasses and, in general, are
> about as
> permanent as fiber base paper. They will still
> benefit from
> proper protective toning or the use of stablizer.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
>
>
=============================================================================================================
> To unsubscribe from this list, go to
> www.freelists.org and logon to your account (the
> same e-mail address and password you set-up when you
> subscribed,) and unsubscribe from there.
>
____________________________________________________________________________________
Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news,
photos & more.
http://mobile.yahoo.com/go?refer=1GNXIC
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you subscribed,)
and unsubscribe from there.
Other related posts:
