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Standardization
Standardization must be performed periodically to maintain color measurement accuracy. It is the
means of correcting the system for any changes that occur to the system over time, such as lamp aging.
Thus, system performance depends on good calibration procedures, consistently followed.
It is extremely important that the standards used for standardization be treated with care. They must be
clean and in good condition if standardization is to be successful. If there is any doubt about the
standards being clean, please clean them as described in the Maintenance chapter.
Two levels of standardization are provided: primary and secondary calibrations. Primary calibration
on MultiSensor Software systems is performed in the off-line mode by manually presenting the black
and white instrument standards to the sensor while the sensor is off-line. On SheLyn software systems,
the primary white and black tiles are placed in the automatic tile holder for automatic presentation to the
sensor. This may be done infrequently (every week), but it must be done regularly. Secondary
calibration is performed automatically during on-line operations. The system automatically moves the
sensor to the sealed tile holder and presents the secondary white tile to the sensor at a time interval
selected in the software.
UV filter calibration may also be performed if the UV control option was purchased. This type of
calibration may be performed automatically if the automatic tile holder is installed on the system. This
procedure should be performed every time a primary calibration is done.
The frequency with which standardization must be done depends on the operating conditions, including
temperature conditions at the sensor and the rate at which dirt and contaminants build up on the sensor.
Standardization must be performed at intervals that are short compared to the time required for
significant color measurement changes to occur. These changes may be evaluated by simply reading
one or more of the instrument standards and observing the changes in these readings over time.
Immediately after standardization, the white standard tile should read within ±0.03 units of its factory-
read values in XYZ. Generally, when the white tile readings differ from the factory-read values by more
than ±0.05 units XYZ, standardization should be performed.
Typically, secondary calibration every four hours and primary calibration every week is appropriate.
CAUTION
When using an automatic tile holder, keep hands, samples, and equipment out of the
way of the tile holder drawer and the z-axis. Both of these parts must be allowed to
move freely or damage may result.
Note: The terms "calibration" and "standardization" are used interchangeably in this manual.
3-2
Operation
11/02
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