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Appendix C
Page 117
Optical Specification
The optical specifications for the bar code labels are listed below.
•
Use the white calibration standard to calibrate the print contrast of the Mcbeth PCMII. Be
sure the filter select switch is on position A for all calibration and measurements.
•
The reflectivity of the white background (RW) is the reflectivity measured in the center of
narrow spaces using the Mcbeth PCMII print contrast meter. The RW must be between
70% and 85%. At this measurement, isolated print defects and edge roughness are
avoided.
•
A spot is defined as an area anywhere within the white background in which the reflectivity
is less than 65%. Spots may not be greater than 0.004 inches (0.102 mm) enclosed
diameter. There may be no more than five spots in the bar code area per label. Spots may
not be any closer to each other than 0.01 inches (0.254 mm).
•
The reflectivity of the black areas (RB) may be measured anywhere within any black area on
the barcode. The print contrast signal (PCS) is defined as (RW-RB)/RW and is measured
using the Mcbeth PCMII print contrast meter. PCS must be a minimum of 0.85. Using the
PCS measurement will avoid isolated print defects and edge roughness.
•
A void is an area within a black area where the PCS is less than 0.85. No voids may be
greater than 0.004 inches (0.102 mm) enclosed diameter. There may be no more than five
voids in the bar code area per label. Voids may not be any closer to each other than 0.01
inches (0.254 mm).
NOTE
For additional optical requirements and measurement techniques,
refer to the AIM Uniform Symbol USS-39 specification.