230 PHOTOGRAPHIC FACTS AND FORMULAS 
Water © 1000 ccm 16 oz. 
When the desired tone is obtained, wash well, and dry; 
slightly darker tones are obtained if the print is immersed in 
a 2 per cent solution of sodium carbonate. 
The following is stated to be suitable for bromide but not 
development (gaslight) prints: 
Mercuric chloride 2g 16 gr. 
Potassium chloroplatinite 4g 32 gr. 
Citric acid 18¢ 138 gr. 
Water 1000 ccm 16 oz. 
This should be made up fresh, and gives warm sepias with 
slight staining of the high lights. For cold sepia tones, with 
absence of staining of the whites, add potassium bromide 
1g (8gr.) to the above. Wash well after toning. 
SELENIUM Toninc.—This gives various shades of sepia 
to purplish-red tones (Mailiani) : 
Powdered selenium 2tol0g 15.4to/77 gr. 
Sodium sulphide 100 g 768 gr. 
Water 1000 ccm 16 oz. 
Heat the solution till the selenium dissolves, and dilute as 
required for use. The weaker the bath, the more sepia the 
colour. On diluting the bath, some selenium is thrown down, 
and the solution should be filtered, or the prints after toning 
passed through two or three baths of 1 per cent solution of 
sodium sulphide. Another (Valenta) : 
Selenium 16.5¢ 127 gr. 
Sodium sulphide 200 g 3 1/5 oz. 
Water 1000 ccm 16 oz. 
Heat until dissolved, dilute with 5 to 6 times the volume of 
water, and add pyrocatechin, 1 per cent solution, 20 to 40 ccm 
to every liter or 154 to 307 min. to 16.0z. If the whites are 
tinged, pass the prints through weak baths of acid sulphite 
of soda. 
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