TONING

The (fairly incomplete) Utter & Complete History & Practicum of...

At Process Supplies we've always been involved with the toning aspect of black & white printing, and not so long back we helped to do this on an industrial scale. Tons of sodium sulphide, thiocarbamide, potassium ferricyanide and caustic soda passed through our doors to brew up vast vats of sepia toner... 'the great stink of Clerkenwell' it came to be known as...

Perhaps not quite, but the glory days of professional toning are behind us now, and thanks to Health & Safety it's altogether a more sedate and controlled activity now.

SELENIUM TONER ~ Kodak Rapid Selenium Toner (the original) referred to in seminal references such as Ansel Adams 'The Print'. Essential to the serious printer, both for permanising and the subtle enhancement it can bring to a well crafted print. Odourless, but one has to be careful with it none the less, it's absorbed through the skin, exhaled as fumes something like garlic, & it's still something of a surprise that the powers that be haven't tried to ban it yet. Another excellent selenium toner is available under the Harman label; Harman Selenium Toner 1 litre as well as Fotospeed

BROWN TONER ~ as opposed to a sepia toner, where the image is bleached out before darkening again in a sulphide bath, a genuine Brown Toner does the same job by brute strength accompanied by an almighty stench. Sulphiding is carried out but in a single bath, using an active & loosely defined sulphur compound called potassium sulphide, or polysulphide. As the toner acts on the unbleached silver, there is no loss of density, and the image colour can be carefully controlled. Hardly surprisingly, in today's climate where chemical photography is under intense scrutiny the Kodak Brown Toner which used this is now discontinued. Another casualty was Agfa Viradon, a similar brown toner.

However one industry's toxic spectre is another's meat + 2 veg, the chemical is easily obtained as an aid to distressing jewellery; try a search under 'liver of sulphur' & it's suddenly not so unpleasant after all... It's a very simple formula; Water 750ml Liver of Sulphur (potassium polysulphide) 7.5g Sodium Carbonate anhydrous 2.2g Water to make 1litre However we should point out that the bad egg smell is hydrogen sulphide which IS toxic, and it's not good for unexposed film and paper either, so best conducted outdoors.

Kodak POLYTONER ~ A versatile hybrid between Selenium Toner and Brown (sulphide) Toner, this was previously produced & marketed by Kodak but discontinued in about 2004. However Kodak in a rare show of generosity went public & published the formula, or at least a very close substitute. However it involves mixing selenium powder, so don't do it at home, (could add 'or anywhere else'...)

[to be continued]