Re: The Ultimate Toner?

Philip Jackson (pjackson@nla.gov.au)
Mon, 6 Nov 1995 20:21:16 +22303754 (EETDT)

According to L.F.A. Mason, Photographic Processing Chemistry, 2nd ed.,
1975, p. 220 the "Manotone" toner was a solution of thiourea dioxide -
maybe this is related to formamidine sulphinic acid - or is it safer
substitute? (Don't ask me, I didn't know thiourea was thiocarbamide;-)

In George L. Wakefield's 19 page pamphlet, A New Method of Toning
Photographs: A Comprehensive Guide to the Use of Manotone, London:
Fountain Press, 1953, he describes Manotone as a white crystalline powder,
with a pH of 4 as a 1% solution, no more toxic than other photographic
chemicals; slightly more toxic to mice than sodium bisulphite. As this
booket is probably pretty rare, here's a summary:

The bleach is similar to that for sulphide toning
Potassium ferricyanide 50 g
Potassium bromide 50 g
Warm water to make 1 litre
Use undiluted and discard when it fails to work

Darkener
Stock solution A (1% solution)
Manotone 10 g
Water not above 32 oC 1 litre

Stock solution B (10% solution)
Sodium carbonate (anhydrous) 100 g
or sodium carbonate (crystalline) 270 g
Water to 1 litre

The toner works best with rapid chlorobromides developed for black tones;
tones from engraving black to to chalk red are produced with ease.

Bromides also tone admirably but the colours tend to be restricted to
sepias and warm browns. Chalk reds are possible but not as easily; colours
reminiscent of a first-class gold toned P.O.P. can be secured and these
are most attractive.

Chloride papers can be toned to sepia (otherwise quite difficult) but
colours tend to be colder.

Unlike sulphide toning density tends to slightly increase - even from
1.8 to 2, giving a characteristic richness and sparkle. Prints should
be developed adequately, fixed properly and washed completely.

The following table shows the colours obtainable with varying proportions
of the A and B stock solutions when toning rapid chlorobromide papers.
(More sodium carbonate results in a more rapid reduction of the silver
bromide or chloride to finely divided metallic silver thereby warming the
colour of the image).

Approximate cold sepia warm brown warm
image colour sepia sepia brown
Parts of A 125 125 125 125 125
Parts of B 25 50 75 100 125
Parts of water 100 75 50 25 -

Quantities are to make 250 ml, enough for an 8x10 tray to tone six prints.
Life of mixed solution is about half an hour.

Increasing temperature speeds up toning and results in warmer tones -
about 3 oC will result in just noticable differences. Red chalk tones are
achieved with equal parts A and B and a fairly high temperature.

A 5% solution of sodium or potassium hydrate can be substituted for sodium
carbonate as the alkali, giving a range of colours starting at sepia and
becoming warmer up to a point, and then colder again as the darkening
becomes more rapid, finally reaching a cold purple black. A 10% solution
of anhydrous sodium carbonate is less caustic (A in the table below; B is
a 2% solution of "Manotone")

Parts of A 5 5 5 5 5
Parts of B 1 2 3 4 5

At 21 oC these mixtures (without water) give tones from warm sepia to a rich
brown colder than plain chocolate. 5 parts A and 2 parts B give the
warmest tones. Other alkalis can be tried - ammonia gives almost olive green
tones but is difficult to use.

Peter, I hope this is enough to get your students started. Nine pounds a
litre sounds pretty exorbitant for a 1% solution of thiourea dioxide, if
the Speedibrews product is really just Manotone under another name!

Philip Jackson