196 PHOTOGRAPHIC FACTS AND FORMULAS. 
After printing, the material should be immersed in salt 
solution, washed and toned as usual, if desired. 
Thin veneer wood can be sensitised; maple and plane give 
the best results; pear is less satisfactory. The wood should 
be immersed for at least 5 minutes in: 
Soft gelatine 37. De 288 gr. 
Water 1000 ccm 16 oz. 
Soak, melt by heat, and add: 
Formaldehyde 7.5 ccm 58 min. 
Dry with moderate heat, and immerse 5 minutes in: 
Hard gelatine 25¢ 192 gr. 
Soluble starch 100 g 768 gr. 
Ammonium chloride 10¢g 77 gr. 
Water 1000 ccm 16 oz. 
Again dry, and sensitise in: 
Silver nitrate 100 g 768 gr. 
Citric acid 83 g 637 gr. 
Water 1000 ccm 16 oz. 
Dry quickly. Print deeply from contrasty negatives, wash 
and tone as usual. 
The sensitising of leather, such as split calfskin, is an easy 
matter, but it will not keep after sensitising. It is advisable 
to coat it first with plain collodion and then with a collodio- 
chloride emulsion. Or the following may be used: 
Hard gelatine 2.5¢g 19 gr. 
Soluble starch 10g 77 gr. 
Potassium bromide 8.75 g 67 gr. 
Cadmium bromide 8.75 g 67 gr. 
Cadmium iodide 2.9:¢ 19 gr. 
Ammonium chloride 2.5¢ 19 gr. 
Water 1000 ccm 16 oz. 
Saturate the material, dry quickly, and sensitise in: 
Silver nitrate 40g 307 gr. 
