Barcodes: Colours and Contrast

Barcodes are an essential tool in the production and warehousing industries. If you haven’t already read our Introduction to Barcodes, it’s a very good starting point for everything you need to know about barcodes.

But how do colour and contrast affect the scan-ability of a barcode? It’s important to understand how barcodes and barcode scanners work, in order to ensure that they will scan every time.

In simple terms, laser barcode scanners shine a light of a certain frequency onto the barcode and a sensor reads the intensity of the light reflected back from the barcode. Darker areas reflect back with less intensity, making it possible for the scanner to read the barcode.

Digital scanners simply take a snapshot of the barcode and analyse the image, converting the pattern of black and white bars into a number.

Good contrast

With this understanding, it’s logical that a barcode requires good contrast between the barcode itself and its negative space in order for the scanner to make a distinction. The most common reason a barcode will fail to scan is because of poor contrast.

Colour affects contrast. For most applications, a simple black-on-white barcode is the ideal choice. But what happens if you require a colour combination? There are a number of rules that should be followed:

• The bars or the barcode should always be darker than the negative space. A reversed barcode will not scan.
• Warm colours such as red, yellow, white and orange are not seen by the scanner and are good for background colours but not for the barcode itself. Red and similar colours will not be seen at all by a laser scanner.
• Colder colours such as green, black and blue are good for bars but not for background colours.
• Always leave a light zone – a few millimetres space around the barcode. This is essential for scanning.
• When in doubt, it’s better to use very dark colours for the bars and very light colours for the negative space.

Some examples of good and back colour combinations for barcodes:

Material affects contrast. It’s important to remember that the material you choose for your barcode also affects its contrast. Even a slight reflection on the surface of the barcode can affect its ability to be scanned. Even a transparent overlay over a barcode, if it reflects light, will prevent the scan of the barcode. So keep the area clear. Inks that reflect light should also be avoided.

When integrating TransLution™ into your production and manufacturing processes, we can help you to decide on the best barcode solutions for your requirements.

Contact us with any questions you may have about getting started with TransLution™ Software.