COLOUR |PHOTOGRAPEY 349 
plate is exposed in close contact with the taking screen, 
developed in the usual way and fixed, washed and dried. 
From this negative a positive is printed by contact and bound 
up with a viewing screen. 
As a rough guide the exposure with f:8 in good light with 
sunshine for an open landscape is about % second. For 
portraiture, head and shoulders, outdoors in diffused light, 
f:8, about 3 seconds. Snap shots should not be attempted 
except in the brightest light at f:6.5 and not less than 1/10 
second.. The speed of the plate is approximately 11 Watkins, 
F24 Wynne with filter and taking screen. A special devel- 
oper is issued by the makers, but any one may be used if 
diluted with an equal volume of water. Green light or total 
darkness must be used, unless desensitising is adopted. 
The transparency must be of a black tone, free from fog, 
brilliant and full of detail. Special plates and developers are 
made for this work. 
Tue AGFA PLATE.—This plate is of the combined type, 
like the Autochrome, and must be placed in the plateholder 
glass side to the lens. A special compensating filter is obtain- 
able, which may be placed in front of or behind the lens, and 
in the latter position it lengthens the focus about 1.5 mm. 
The exposure is about 60 to 80 times that required for a rapid 
plate and for a sunny landscape about midday with f:6.8 one 
second exposure should be correct. 
The developer recommended is: 
Metol 1Z25)2 96 gr. 
Hydrochinon 5g 384 gr. 
Sodium sulphite, dry 80 g 614 gr. 
Potassium bromide 48¢ 37 er. 
Ammonia, sp. gr. 0.91 25.9 ccm 196 min. 
Water 1000 ccm 16 oz. 
Dissolve the metol and hydrochinon in warm water and add 
