[pure-silver] Re: b&w print has discolored - selenium toning RC
- From: "Jason McPeak" <mcpeak.jason@xxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Thu, 27 Mar 2008 11:57:37 -0500
I usually only tone my negatives if it's something really really good I used
as subject matter. You can use SELENIUM toner to tone negatives, it also
increases your D-MAX slightly as well. Selenium is a good antioxidant.
On 3/27/08, Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
>
> At 08:39 AM 3/27/2008, you wrote:
> >Does anyone on the list tone their processed film?
> >
> >I've never toned my film, depending on the wash to bring it to a
> >stable-enough state. Looking at negs from 25+ years ago, I see no
> >discoloration...
> >
> >
> >
> >> To be reasonably permanent any paper or film must be
> >> completely fixed so that all of the unused halides are converted
> >> to a soluble form, and must be adequately washed so as to remove
> >> these materials and the bulk of the hypo.
> >
>
>
> For the most part pictorial film is quite coarse grained
> compared to microfilm or printing paper emulsions. The vulnerability
> of the image to peroxides is to some degree dependant on the grains
> size being greater as the grains become smaller. Also a small amount
> of oxidation may not be noticable on a large pictorial negative where
> it may destroy some of the data recorded on microfilm.
> However, toning provides the same protection to pictorial film.
> The best toners are polysulfide, like KBT or gold toner. Where the
> greatest permanence is desired negatives should be toned. The degree
> of toning is tested by bleaching the silver image from a toned sample
> and measuring the density. The comparitive densities should indicate
> about 60% conversion of the silver to silver sulfide. This is the
> criteria for microfilm. I don't know its applicability to pictorial
> films because, AFAIK, no research has been done on them.
> Gold toning can be done with a couple of formulas. The one most
> often used for microfilm is Kodak GP-2. I don't know the relative
> merits of polysulfide vs: gold toners for protection. AFAIK, gold has
> been the standard for decades but is quite expensive compared to the
> sulfide toner.
> According to Doug Nishimura, of IPI, Kodak Brown Toner or
> formula T-8 is suitable for microfilm or prints. IPI came up with a
> formula for a polysulfide toner to insure that no one would have to
> rely on a commercial product that might change as had KRST. IPI's
> formula is relatively oder free where KBT has a strong hydrogen
> sulfide (rotten egg) odor. I think also that the IPI formula works at
> room temperature where KBT works very slowly unless heated to about 100F.
> In any case there is probably no reason to routinely tone
> pictorial negatives unless one knows they might be stored in an
> uncontrolled environment or wants to insure maximum life. Note that
> there are plenty of negatives older than a century that received no
> special treatment.
>
>
>
>
>
> --
> 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.
>
--
I am a leaf on the wind! Watch how I soar.
-Hoban "Wash" Washburn
(serenity movie)
-----------------------------------------------------------------------
http://mcpeak.jason.googlepages.com/home
Other related posts:
