is a uniform illumination of the entire copy-board and, simultaneously, a reaso- 
nably limited radiation of heat from the light source that does not damage the film. 
  
Fig. 10. Diagram of control rod system 
for fulfilment of Scheimpflug 
principle. 
The result of these considerations 
is the recently completed Rectifier 
SEG V of which Fig. 8 shows a 
schematic diagram and Fig. 13 a total 
view. 
Some essential new features will 
be dealt with first. The 1 X 1 m? 
copy-board is mounted in its centre mum height 3.6 m. Weight 800 
on a ball-and-socket joint and is kg. 1000-watt lamp with lens 
therefore for the first time freely ac- condenser. 
cessible from three sides. It may be 
tilted with the aid of 2 handwheels in 2 directions perpendicular to each other. 
Experience has shown that this design is particularly suited for the application 
special design of thedistortion free Topogon 1:6,3/f = 18 cm. The lens mount in- 
of the point process. Instead of the former Dagor lens, the rectifier employs a 
corporates an automatic exposure timer permitting to set exposures from 2 to 60 
seconds. 
The lighting system of rectifying units usually presents the most serious 
problems. Large-size pictures should be reproduced within a wide range of magni- 
fication avoiding any shadows and with an illumination allowing finest work. 
Due to the considerable radiation of heat, modern lamps with a maximum of 
illuminating intensity are not suited for this purpose. Flood-lighting systems 
consisting of fluorescent tubes either supply an illuminating intensity which is 
  
Fig. 11. ‘Steam Hammer’, 1925. Magni- 
fication up to 5 times. Mini- 
14