The In-Line Densitometer (ILD) measures
film LAD patch densities while film is being transported out of the
processors dry-box. ILD's are in use on 35mm negative and positive processors as well as 65
and 70mm processors. The red, green and blue density readings
are uploaded to a computer or network via an RS422 cable providing
instantaneous density measurements.
This unit is sold as a system which
consists of an ILD, a Pattern Synch Detector (PSD), a power supply for the
ILD, a decoder box for the PSD and a six foot 115 VAC power cord. A PSD is required to trigger the ILD to
read the LAD patch. The PSD pattern, which is what triggers the PSD, must be incorporated into the leader
of the film sample and positioned before the LAD patch. The ILD
measures the density on the centerline of the film while the processor
is operating at speeds up to 1,500 feet per minute.
Calibration of the unit is done once at
the factory. Unlike desktop densitometers, cycling power to the unit
and environmental temperature fluctuation will not effect the calibration.
Tests have shown the repeatability of density readings to be within ±0.002
density over a period of 30 days.
Maintenance of the system consists of
wiping the area above and below the film path with an alcohol swab.
Frequency of cleaning depends on the cleanliness of the environment.