[pure-silver] Re: Hypo-Alum Toner (Photo-Formulary)
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Mon, 4 Oct 2004 21:47:51 -0700
----- Original Message -----
From: "Dave Hornford" <dave@xxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Monday, October 04, 2004 7:38 PM
Subject: [pure-silver] Re: Hypo-Alum Toner (Photo-Formulary)
> Richard,
>
> Thanks
>
> The Formulary calls for Distilled water (52C/125F) &
> Sodium thiosulfate,
> pentahydrate. Then mixing in Potassium alum (alum), with
> the Silver Nitrate
> & Potassium Iodide as options to be added after. (I didn't
> include amounts
> deliberately - I don't believe I have licence to publish
> their formula).
>
> But the document doesn't mention that sulfurization is
> required.
>
> Regards Dave
>
Sodium Thiosulfate, pentahydrate is the crystaline form.
Well, they undoubtedly got their formula from somewhere
else. The Kodak formula is the only one not requiring
boiling at some point. Defender had three variations for
different kinds of paper. One had a gold modifier and one
Potassium iodide, like Kodak T-1a.
The Silver nitrate is necessary when mixing fresh toner
because the toner bleaches the image otherwise. Without the
nitrate it must be "seasoned" by toning scrap prints until
it stops bleaching, or at least, until the bleaching is
reduced to a reasonable level. The iodide produces silver
iodide in the process of toning. It is a tone modifier.
Hypo-Alum toner can be made with a chloride, usually sodium
chloride, an Iodide, or a bromide, or a combination of
these. They affect the tone but I can't tell you in what
direction. Some Hypo-Alum toners contain a small amount of
Gold Chloride (Kodak Gold Medal Toner T-113 and Defender
1-T, which are identical). When an image toned in a
sulfiding sepia toner (as distinct from Selenium or Copper
toners) it will turn the image brick red. When added to the
toner is shifts the tone towards red. Nelson's Gold Toner is
a more satisfactory gold modified direct toner than the
Hypo-Alum modifications. The best source of instruction for
Nelson's is the patent. It is USP 1,849,245 available
on-line from the US Patent and Trade-Mark office at
http://www.uspto.gov You will need a plug-in to read the
FAX TIFF files the patent images are in. The best is
Alternatiff, which is free-ware. A Google search will take
you to their web site.
Here, for reference, is Defender's simplest Hypo-Alum
formula, intended for Velour Black and other Bromide papers.
Defender 2-T Hypo-Alum Toner
Solution A
Boiling water 4.0 liters
Sodium Thiosulfate, crystaline 480.0 grams
Potassium Alum 120.0 grams
Dissolve the thiosulfate thoroughly before adding the
Alum. The mixture should be boiled for a few minutes, then
allowed to cool.
When cool add the following.
Water 30.0 ml
Silver nitrate, crystals 1.4 grams
Sodium Chloride 1.4 grams
Dissolve the silver nitrate first and then add the
sodium chloride when it is thoroughly dissolved. The entire
solution, including any precipitate should be added to
Solution A with stirring.
The completed toning bath should be allowed to stand for
several hours in order to "ripen".
To use place in a tray in a water bath and heat to a
temperature not to exceed 120F. Prints will tone in 15 to 30
minutes at the above temperature.
Handle prints face up. Move them around a little at the
start and reove all air besss from the surface by means of
cotton swabs. Toned prints should be thoroughly washed in
several changes of water. Waxh water should be too cold at
the start. A sudden change of temperature from the earm
toning bath to cold tap water will sometimes cause blisters.
Black and white prints can be toned int he above sepia
toner directly after than have been developed and fixed in
the usual manner.
The Silver Nitrate prenvents bleaching and should be
present in the formula in the exact qualitity give above at
the start of toning. Excess of silver nitrate will "clog"
toe toning bath and is apt sometimes to cause bluish tones.
In one of its other formulas, the one with the Gold
Chloride, it is instructed that the prints be fixed again
for five minutes after toning. This may be to harden them or
it may be that the Gold Cloride version produces some free
halide. Re-fixing is definitely necessary after Nelson's,
but it works somewhat differently than the above. The
remarks pertaining to mixing and using apply to all such
toners.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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