32. PHOTOGRAPHIC FACTS AND FORMULAS 
Crystal caramel powder 500 g 5 oz. 
Gum arabic 250 ¢ 2 oz. 
Water 750 ccm 74 02. 
Or: 
Caramel powder 500 g 10 oz. 
Water 250 g 5 oz. 
Denatured aicohol (methylated 
spirit ) 150 ¢g 3 02. 
Mix and strain through muslin. Ordinary caramel or the 
above may be mixed with a thick gum arabic solution and 
burnt sienna or lampblack in equal weights. Or the follow- 
ing may be used: | 
Dextrine 50 g Y4 oz. 
Crystal caramel 200 g 1 oz. 
Ammonium chloride 4.5¢ 10 gr. 
Water 200 ccm 1 oz. 
Alcohol 200 ccm 1 oz. 
Glycerine 25 ccm 60 min. 
Work up into a stiff paste. | 
ASPHALT Bacxinc.—Dissolve powdered asphalt in ben- 
zole, chloroform or, preferably, carbon tetrachloride, to form 
a dark brown liquid. Apply with a brush. This dries very 
rapidly. 
Cornvu’s BacKInG.— 
Oil of cloves 6 parts 
Turpentine 7 parts 
Lampblack q.s. 
Use enough lampblack to form a stiff paste. This takes a 
long time to dry and has a very strong smell. 
STAINED COLLODIONS.— 
Aurine 45¢ 35 gr. 
Enamel collodion 1000 ccm 16 oz. 
