147 
Technical specifications( resolution, size of 
translucent screen, possibility of processing 
large—format images, photorecording on roll 
materials) of the compositing device PC—4 are 
significantly higher than other instruments of the 
same destination. 
The device is a complex optical and mechanical 
system and consists of a file of mechanical and 
electrical units: four illuminating and projecting 
channels each of them with a light source, 
iliuminant, contact frame projecting objective,lens 
light filters turret, shutter, carriage with the 
holding frames? reflecting mirrow, translucent screen 
of 500x500 mm size, power supply unit, command board, 
photorecording, etc. 
The image holders have all necessary degrees of 
freedom which allow to coincide on a screen device 
the spectral images projected by parts (100 x 100 mm 
of positive)by each of the channel, and the image 
holders carriages provide for a change of projecting 
of any other part of the initial image without 
disturbance of channel image registration on the 
screen . 
The multitime change of an enlargement in each 
of the channels with -*— 1% of the nominal value is 
provided. 
The photorecording is done on a photo material 
of 530 mm wide. Photographic resolution of each 
projecting channel is not less than 15 lin/mm. 
In the translucent screen of the instrument 
there is used the matted film with wide indicatrix of 
diffusion, which allows to observe the image on the 
screen far from the screen centre without bnghthness 
distubances. The screen for photorecording is taken 
of f .