Figure 4.—Planekator for checking surface flatness. 
Provision is made for three modes of projector-light balancing: (1) manual 
rheostats on the control panel, (2) fingertip control through small rheostats 
on the tracing table coupled with saturable reactors, and (3) automatic 
balancing by means of the Autolum^. The electrical system is designed to 
operate any of the double-projection systems listed in Table 1, without 
alterations. It is also designed to operate all of the types of pantographs 
normally used with double-projection plotters. 
NEW PROJECTORS 
The recently improved K-5 projector (see figure 5) is now equipped 
with a ball-bearing swing motion and with the lens and lens cone built 
together as an integral unit. The K-5 projectors accommodate convergent, as 
well as vertical, photography with provision for satisfying the Scheimpflug 
condition. By inserting the appropriate lens-and-cone assemblies, the K-5 
projectors can be used with the universal frame for projection at either 
525 or 760 millimeters. 
6 
Autolum is the trade name used by the manufacturer, Watson Electronics & 
Engineering Co., Arlington, Virginia. 
6