Determine circulation software to be used. Each software package has it’s own "rules and regulations" governing the bar codes that will work with it. Each package may require a specific symbology; a special designator (numeric or alpha character) for patron or item label, a fixed or flexible total number of characters, as well as a required Check Digit or not.

Determine Symbology*. There are three basic symbologies that most software packages support: Codabar, Code 39 (Code 3 of 9), and Interleaved 2 of 5. Software determines which you need.

Determine if a pre-designated number or alpha character is required. Most software packages use a pre-designated numerical or alpha character to verify that an item (book, periodical, video, etc.) doesn’t get accidentally used as a patron or student number.

Choose bar code type and style. There are three standard styles: single, double and pair.

• Single bar codes are used on the outside or the inside of the item. Double bar code includes one "live" bar code label and an extra strip with the eye-readable number only for use on the shelf list or book’s card or may be placed somewhere else inside the book itself. Pairs consist of two "live" labels (one for outside or inside the book and another for outside or inside the book or for on the shelf list).
• Digital bar codes are the latest in technology and most durable bar codes available. Imaged on 4-mil 60-lb. white paper with a 1-mil permanent archival-safe acrylic adhesive. Advantages include: 100% guaranteed first time read-rate; higher print-contrast ratio than photocomposed; archival quality; no change in adhesive; greater abrasion resistance than all other technologies; and a lower cost than photocomposed. Laser bar codes are produced on a 1200 dpi printer on 24 lb. smudge-proof paper with a gloss or matte laminate coating for durability, and are available in five background colors plus white.
• Thermal bar codes are printed on a 2-mil polyester material with a matte finish laminate for durability and are offered in four colors and three design configurations.

Always request a bar code sample to verify the quality. Different types of production of bar codes will vary in quality and quality is essential to a good "read." A bar code is read when a beam or spot of light from a scanner is passed over the bars. The black bars absorb the light and the spaces reflect the light back to the scanner. The mathematical differences in reflection are translated into electrical signals. These signals are then converted into binary ones and zeros, which form various combinations equaling letters and numbers. Some lower line production methods may produce voids in the inked area (bars) that may be misinterpreted as a space by the scanner, or the ink may "overspray" into the space area between the bars and may also cause a misread.

When applying bar codes NEVER apply hand lotion beforehand. Depending on the print quality of the bar code and the substrate material of the label, hand lotion may cause ink to smear. Lotion may also cause the protector (if used) not to adhere properly to the label or even make grease spots on the label that can interfere with readability.