[pure-silver] Re: Hypo-Alum Toner (Photo-Formulary)

----- 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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