Barcodes on packaging: GS1 Australia, sizing, placement and why they fail

Get the number right first: GTINs and GS1 Australia

A barcode encodes a Global Trade Item Number, a GTIN. In Australia, GTINs are allocated to a company by GS1 Australia through membership, and every variant of every product that is sold separately needs its own: each flavour, each size, each pack count, and a new GTIN when the product changes materially. Retailers check the number against the GS1 registry. A number bought cheaply from an online reseller, or invented, will not match a registered company and will be rejected at ranging.

• Join GS1 Australia and allocate GTINs from your company prefix. Fees scale with turnover.
• The consumer unit uses a GTIN-13 (13 digits). The carton uses a GTIN-14, which is the same base number with a packaging indicator digit in front.
• Keep a register of which GTIN belongs to which SKU, format and count. Retailers will ask for it in their product data forms.
• Never reuse a retired GTIN on a different product.

The right barcode for each level

Woolworths states outright that UPC-12, UPC-A and UPC-E will not scan in its distribution centres, and both major retailers expect the correct symbology at each level. A retail EAN-13 on the outside of a carton is one of the commonest reasons a first delivery gets held.

Size and magnification

Barcodes are specified as a percentage of a nominal size. For an EAN-13, 100 percent magnification is 37.29 mm wide by 25.93 mm tall including the human-readable digits below the bars, with a bar height of 22.85 mm and a narrowest bar (the X-dimension) of 0.33 mm. GS1 permits 80 to 200 percent for retail point-of-sale scanning.

The ITF-14 on cartons is larger and coarser because it is scanned at a distance on a moving conveyor: the specified range for general distribution scanning is 50 to 100 percent of a nominal symbol whose X-dimension is 1.016 mm, with quiet zones of about 10 mm, and it normally carries bearer bars (the black frame) when printed directly onto corrugated board so the flutes do not distort the read.

Quiet zones

The light margins to the left and right of the bars are part of the symbol. At 100 percent an EAN-13 needs 3.63 mm clear on the left and 2.31 mm on the right, scaling with magnification. Anything that intrudes, a border, a panel edge, a graphic, a fold, stops the scan. Many designers add the small 'greater than' chevron on the right as a visual guard for the quiet zone, which GS1 recommends. Keep the quiet zones clear on every proof, including after the dieline is applied, because a bleed that runs over the margin fails just as surely as a logo does.

Colour and contrast

Scanners read in red light. Anything that reflects red reads as white; anything that absorbs it reads as black. That gives simple rules:

• Bars: black, dark blue, dark green, dark brown. Never red, orange, pink or yellow. Never metallic.
• Background: white, or light yellow, orange, pink or red. Never dark, never metallic, never a photograph.
• Reversed-out barcodes (light bars on a dark ground) do not scan. If the pack is dark, print a white or light box behind the symbol.
• On metallised film, foil or clear substrates, print a solid white underlay before the bars. On kraft, verify: brown is often too dark for reliable contrast.
• Bars must be one solid ink. Do not build black from four-colour process; registration shift will blur the edges.

Placement on the pack

• Lower right of the back panel is the convention shoppers, checkout staff and self-checkout scanners expect. Anywhere else costs seconds per item, which retailers notice.
• Flat, not across a seam, crimp, fold, corner or the curve of a bottle. On cylindrical containers, orient the bars so they run around the circumference (ladder orientation) when the diameter is small, so every bar is the same distance from the scanner.
• Away from the edge of the pack and away from where a price ticket or promotional sticker will be applied.
• One barcode per consumer unit. Multipacks carry their own GTIN and the individual units' barcodes must be hidden or marked so they cannot be scanned in error.
• On the carton, follow the retailer's logistics labelling requirements for position: Coles and Woolworths both specify where the ITF-14 and the logistics label sit.

Print process and bar width reduction

Ink spreads on press. Flexo on film spreads more than offset on board. The printer compensates by narrowing the bars in the artwork, a bar width reduction, so that the printed bars come out at the correct width. The right value is the printer's to specify, not the designer's to guess: ask them for it, ask them to apply it, and ask for a verified proof. Supply the barcode as vector artwork generated from GS1-compliant software, never as a screenshot or a low-resolution image, and never scale it non-proportionally.

Verification: prove it before the run

A barcode verifier measures the printed symbol against ISO/IEC 15416 and grades it A to F on contrast, edge definition, decodability and more. Retailers want to see a verification report, and Woolworths requires one for carton barcodes before ranging and again every twelve months. GS1 Australia offers a verification service; so do accredited print and label suppliers. Verify a printed sample from the actual press and substrate, not a laser proof, and keep the report with the product data.

Why barcodes fail: the checklist

• Truncated height.
• Quiet zone intruded by a border, graphic, fold or bleed.
• Red, orange or metallic bars, or bars over a photograph.
• Reversed out of a dark ground with no white box.
• Below 80 percent magnification, or ITF-14 below 50 percent.
• Wrong symbology for the level (EAN-13 on a carton, UPC on anything).
• Placed across a seam, corner or the tight curve of a small bottle.
• Built from four-colour process instead of a single ink.
• No bar width reduction, so bars fill in on press.
• Unregistered or reseller GTIN.

Written by

Morice Kastoun, Founder & Creative Director

Morice Kastoun is the founder and creative director of Morice&Co., an independent Melbourne branding and packaging studio. His packaging has shipped through the compliance processes of Coles, Woolworths, Chemist Warehouse, Priceline, Petbarn, Big W, Myer and Sephora US.