224 PHOTOGRAPHIC FACTS AND FORMULAS 
Water 500 ccm 17¥4 oz. 
Mix into a cream and add slowly with constant stirring pure 
sulphuric acid, sp. gr. 1,845, 70 ccm (1183 min) ; then follow 
the directions given above. The actual toning bath is: 
Ammonium oxalate or sulphate 
solution as above 50 ccm 384 min. 
Oxalic acid, sat. sol. 50 ccm 384 min. 
Ammonia alum, sat. sol. 50 ccm 384 min. 
Ferric oxalate, 20% sol. q. Ss. q. Ss. 
Glycerine 50 ccm 384 min. 
Potassium ferricyanide, 
10% sol. 10 ccm 77 min. 
Water 1000 ccm 16 oz. 
Mix the oxalic acid and vanadium solutions with half the 
water; then add the alum solution and the ferric oxalate; 
mix the ferricyanide solution with the glycerine and the 
remainder of the water, and add to the first solution. The 
more ferric oxalate used, the bluer the colour; with 10 ccm 
(77 min.) in the above bath a bright emerald green tone is 
obtained. Toning takes from 10 to 15 minutes; the prints 
should be immersed in a 10 per cent solution of sodium 
sulphate for 5 minutes, and then washed for 10 minutes. 
Namias suggests the following method of making van- 
adium chloride: 
Ammonium vanadate 100 g 768 gr. 
Hydrochloric acid 250 ccm 4 oz. 
Water 250 ccm 4 oz. 
Sodium bisulphite, dry 60 to 80g 460 to 610 gr. 
Heat until the solution turns blue and dilute to 1000 ccm 
(16 oz.) with water. For green tones bleach the prints in the 
usual ferricyanide bath, wash well, and immerse in: 
Vanadium chloride, as above 25 ccm 192 min. 
Ferric chloride 2.5'g 19 gr. 
