What Makes a Good Barcode?
The International Standards Organization (ISO) has specific standards for barcodes that are meant to define and control all barcodes used throughout the world. A barcode, by definition, is a one-dimensional (flat), printed code. It consists of black and white areas whose relationship to each other makes each barcode unique.
The ISO has determined that there are multiple measuring and grading factors that apply to a standardized barcode.
Edge determination – The number of the bar-and-space transitions is called the global threshold and determines what type of barcode it is. A barcode for a pound of ground beef will have a different amount of bar-and-space transitions than barcode for a flashlight bulb.
Minimum reflectance – Measurement of the dark areas of the bar compared to the light reflected by the light parts of the bar. The light (white) areas must be more than double that of the dark areas for the scanner to be able to read the barcode.
Minimum edge contrast – Measures the contrast difference between adjacent bars and spaces. Simply put, there should be no shades of grey. Every portion of the barcode must be either black or white.
Defects – Light spots in dark areas or dark spots in light areas, might be caused by faulty printing equipment or a dirty environment. Barcode printers are designed specifically to print clean and crisp barcodes all the time.
Decodability – The measurement and pattern of all bars and spaces used in a calculated formula to determine what the barcode actually means (“ground beef” or “flashlight bulb”). This measure relates to the accuracy of the dark bars and light spaces.
Quiet Zone – The necessary space on the left and right sides of the barcode must be adequate and not crowded by other printed matter.
If you’ve ever taken a close look at a barcode, it’s easy to imagine all the things that could go wrong when it gets printed. Even a small flaw in a barcode can render it unreadable, or even change its meaning. While barcodes can be printed on any kind of printer, a dedicated barcode printer has taken into account all the parameters set down by the ISO for barcodes.