32 | APPENDIX B: BAR CODE LABEL SPECIFICATIONS
Appendix B
Bar Code Label
Specifications
All bar code symbols/labels should satisfy the appropriate AIM Uniform
Symbology Specification.
Background Substrate:
The bar code symbol should be printed on material (media) that is reflective
and has a matte (not glossy) finish. A background diffuse reflectance of at
least 70% to 80% is desirable for optimum contrast. Retro-reflective media
should be used to obtain decode distances greater than 36 inches.
Ink Color and Type:
The inked bars should not exceed 25% reflectance at the wavelength that is
being used for reading, whether printed with black ink or colored ink. The
reflectance value should not vary more than 5% within the same character.
Voids and Specks:
The code should be printed clearly, free of voids, specks, blemishes and
lines that could “fool” the scanner. Specks or blemishes in the white
spaces, or false or missing bar sections could be interpreted by the reading
equipment as part of the code. Generally, the width of such flaws is more
serious than the height. Code symbols/ labels should be rejected if these
defects are present.
Definition:
The bars in the bar code symbol should be well defined. Their edges should
not be rough or fuzzy, so that the bars and spaces have the proper widths
intended for the bar code symbology used.
Contrast:
Background reflectance (that of the substrate on which the codes are
printed) should always provide a good contrast relative to the ink
reflectance (that of the code bars). The difference between the two should
be at least 37.5% at the wavelength used for reading.
Tolerance:
The ratio of the widths of bars and spaces in a bar code symbol must
conform to the appropriate AIM bar code specifications and can cause
problems if not correct throughout the bar code. Problems can occur when
bar edges are smeared or rough, or when they exhibit voids.
