Barcodes

Symbology

Light margins

The 'light margin' (or quiet zone) is a solid light area to the left and right of the barcode. These areas are very important as they enable the scanner to recognise where the barcode begins and ends. The width of this light margin depends on the size of the barcode. Insufficient light margin areas can cause scanning difficulties. Always ensure that the light margin areas are kept clear of any text or graphics of any colour.

Checking barcode print quality and bar width

Always ensure that the print quality of the barcode is of a high standard. Make sure the dark bars are clear crisp and well defined. Watch for voids and smudging. Poor print quality can also cause scanning difficulties. Ensure that bar widths are correctly maintained throughout the printing process.

Choosing colours

Because a scanner reads a barcode using an infrared light source, it sees the barcode differently to the human eye. As a result, some colour combinations are unsuitable for scanning, because they don't provide sufficient contrast between the dark bars and the light background.

Below are a few examples of suitable and unsuitable combinations:

Scannable colour combinations		Non scannable colour combinations
	Black bars on white background		Yellow bars on white background
	Blue bars on white background		Orange bars on white background
	Black bars on orange background		Red bars on white background
	Blue bars on orange background		Red bars on light brown background
	Black bars on red background		Light brown bars on white background
	Green bars on white background		Black bars on green background
	Blue bars on red background		Black bars on blue background
	Black bars on yellow background		Black bars on dark brown background
	Blue bars on yellow background		Black bars on blue/green background
	Green bars on yellow background		Blue/green bars on black background

Packaging considerations

Always avoid locating the barcode around edges, under flaps or where there are seams or seals in the packaging.

To ensure that barcodes scan correctly before the item goes to market, GS1 Australia offers a 'Barcode Verification Service'. GS1 BarCodes are tested for scannability and adherence to GS1 specifications. Most retailers will expect to see a copy of this report before they will accept a product for retail display.

View more information on Barcode Verification.

Note: This information acts only as a guide. For more detailed information or to obtain an GS1 BarCode size gauge, please contact our Technical Help Desk on 1300 366 033.

View the collection of GS1 Australia Technical Fact Sheets.