156 PHOTOGRAPHIC FACTS AND FORMULAS 
CRYSTAL VARNISHES.—TLhese are sometimes used for lan- 
tern slides and transparencies: 
Gum dammar 125 ¢ 2 oz. 
Benzol 1000 ccm 16 oz. 
Or: 
Fused amber 125 ¢ 2 oz. 
Chloroform 1000 ccm 16 oz. 
Cor: 
Fused amber 200 g 3 0Z: 
Gum sandarac 300 g 4Y4 oz. 
Gum elemi 50 g 384 gr. 
Alcohol 1000 ccm 16 oz. 
Camphor 6g 46 er. 
RETOUCHING VARNISHES.—Since the gelatine film, as well 
as many of the varnishes, will not take kindly to the retouch- 
ing pencil, it is customary to apply locally a retouching 
varnish or medium which leaves a surface with a slight tooth. 
These should be applied in very small quantities, a drop or 
two, gently rubbed with a circular motion with the finger tip 
over the part to be retouched, and then allowed to dry: 
Gum dammar 20 g 96 gr. 
Turpentine, refined 100 ccm Loz: 
Or: 
Powdered resin 12.5.2 60 gr. 
Turpentine, refined 100 ccm 1 oz. 
6ors 
Gum dammar 6.6 g 32 oe: 
Turpentine, refined 50 ccm YZ oz. 
Benzol 50 ccm 4 oz. 
Oil of lavender 50 drops 10 drops 
Or: 
Gum dammar 20 g 154 gr. 
Venice turpentine 10g 77 gr. 
