When a UPC is required, high standards are strictly enforced. In some cases, a non-readable UPC can cost product owners fines, concessions to retailers, and worse yet, product pulled off shelves never to be sold. Therefore, it is important to understand what is involved in the creation of a quality, readable UPC.
ANATOMY OF A UPC
Number System Character - the first number of the UPC, this number assigned by the Uniform
Code Council simply indicates the number system that is to follow.
Number - a unique 5 digit number assigned by the Uniform Code
Item Number - a 5 digit number
assigned and controlled by the product owner.
Check Character - the last number of
the UPC, it is used to verify the accuracy of the entire UPC.
IMPORTANT UPC CHARACTERISTICS
1. Size - the nominal size
is 1.469" wide x 1.02" high including the number system and
check characters. The minimum recommended size, 80% of the nominal size,
is 1.175" wide x .816" high. The maximum recommended size,
200% of the nominal size, is 2.938" wide x 2.04" high. In
general, larger UPC's scan better. Size may vary depending on package design
and printing conditions.
Contrast - the level of contrast
between bars and spaces helps determine the readability of a bar code.
Although many color combinations may be used, the most reliable combination
is black bars with white spaces. If that combination is not feasible,
an alternative combination of dark bars with light spaces is always
recommended. Since the scanner uses infrared light to read the bar code,
the color red cannot be scanned and therefore should not be used as
any part of the UPC.
Quiet Zone - the required area
to the left and right of the bar code free of all printing, this area
prepares the scanner for the bar code that is to follow. Since bar codes
can be read from either direction, quiet zones are required on both
Bar/Space Pattern - every number has
a unique pattern of bars and spaces of varying widths. Accurate printing
of these patterns and their widths is essential.
Location - The UPC should be
located in the center of the package's "natural bottom". This
is determined by considering the design of the container as well as
the orientation of the package graphics.
2. Show-Through - Show-through can
occur with transparent or translucent packages when the product is seen
through the spaces of a bar code. This can yield a bar code unreadable
and can be avoided by overlaying an opaque white background with dark
Truncation - Truncation is decreasing
the height but not the width of a bar code. Although not recommended,
truncation is sometimes necessary. Manufactures should try to reduce
the bar code within the established limits before cutting off the top
of the bar code through truncation.
4. Printing Methods - Different printing
methods effect the image quality of a UPC in
different ways and, therefore, steps must be taken to counteract any
negative effects. For example, in silk screening, the occurrence of
ink spread must be calculated and bar width reduction must be incorporated
into the film master. Ink spread can also decrease the flexibility of
size reduction of a bar code. If a bar code is reduced too much, an
attempt to silk screen it will blur the bars together. This is one of
the reasons why it is recommended to keep the bar code within the minimum
of 80% of the nominal size.
The printing methods also affect the position of the bar code. With any method that might involve ink spread, it is best to position the bar code on its side so that the bars run in the same direction as the ink flows during the printing process. This insures that any blurring will affect bar length rather than bar width, which is more crucial to readability.