250 PHOTOGRAPHIC FACTS AND FORMULAS 
Red brown.—Indian ink 6, carmine 8, Vandyke brown 8 
parts. 
Sepia.—Lamp black 4, sepia 35 parts. 
Pure black —Indian ink 15, Vandyke brown 2, Venetian 
red 2 parts. 
Violet black—Indian ink 20, indigo 2, carmine 1 part. 
Red chalk.—English red 10, Italian red 5, lamp black 0.03 
parts. 
Transparency tissue for enlarged negatives, and positives. 
—Indian ink 2, Indian red 3, carmine lake 5 parts. 
To Coat sy Hanp.—Strain the warm mixture into a flat 
dish standing in warm water, and clear the bubbles off the 
surface with a strip of paper or thin card. Hold the paper 
to be coated upright at the further end of the dish, its lower 
edge just touching the liquid, and gently lower it on to the 
surface. Float for 2 minutes, and raise with a steady mo- 
tion; allow to drip and hang up to dry. 
SENSITISING.—Either ammonium or potassium bichromate 
may be used: 
Potassium bichromate 21 to 63g 160 to 480 gr. 
Water 1000 ccm 16 oz. 
Ammonia q. S. q. Ss. 
Enough ammonia should be used to make the solution smell 
distinctly. For weak negatives use the weakest bath, for 
normal negatives the mean, and for harsh negatives the 
strongest bath. Immerse the tissue for 3 minutes, and dry in 
the dark. The temperature of the solution should be 15° C. 
C60" EF.) 
The following gives a tissue that will keep better: 
Potassium bichromate 20 g 240 gr. 
Citric acid i 5g 60 gr. 
Ammonia A NGLd Se qu St 
