TM 5-3610-257-14
a.
Time unit dials. The time unit dials form a decade dialing system. While initially programmed on basis of
"seconds", reference to time unit dials is in "units". For example, each position on left dial is programmed for 10 seconds
but would represent 100 units. Each position on center dial is programmed for 1 second but would represent 10 units, and
each position on right dial is programmed for 1/ 10th of a second but would represent 1 unit. First position (1) on left dial
would be 100 units or 10 seconds, second position (2) would be 200 units or 20 seconds, etc. First position (1) on center
dial would be 10 units or 1 second, second position (2) would be 20 units or 2 seconds, etc. First position (1) on right dial
would be 1 unit or 1/lOth of a second, second position (2) would be 2 units or 2/ 10ths of a second, etc.
b.
DENSITY dials. The control of exposures by the exposure control instrument is accomplished by the DENSITY
dials. Increase or decrease in exposure is the result of density dial settings, plus setting of time unit dials. Combination of
DENSITY dials and time unit dials provides control of exposure that can be predicted, controlled, and repeated. Amount of
time shutter is open and camera lights are on is determined by the coordinated settings of DENSITY dials and time unit
settings. DENSITY dials override time unit dials when using MAIN or HIGHLIGHT UNITS.
For example, if instrument is set with left time unit at number 1, this provides 100 units. Normally phototube is adjusted to
provide 10 seconds at this position when left DENSITY dial is at 1.0 and right DENSITY dial is at .00 (10 seconds at 100
units). When left DENSITY dial is turned to 1.30, exposure cycle becomes 20 seconds. The DENSITY dials increase
exposure cycle in direct relation to densities of copy (see Table 3-3, Density Dial Settings).
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