Mistakes to avoid · Nº 06
Why barcodes don’t scan — and how to fix it
Barcodes fail to scan for a short list of predictable reasons, and poor print contrast is the most common. The rest: too small or low-resolution, no quiet zone, physical damage or a curved surface, dirt, condensation or faded direct-thermal ink, and using a 1D scanner on a 2D code. Fix the print quality and placement and most scan failures disappear.
- 01
Poor print contrast
WhyLow contrast between the bars and the background is the single most common cause — a scanner needs dark bars on a light background to read the pattern.
FixPrint dark (black) on white; avoid coloured, reflective or busy backgrounds behind the code.
- 02
Too small or low-resolution
WhyShrinking a barcode to fit, or printing it at low resolution, loses the fine bar detail a scanner needs.
FixSize the barcode properly and print at full resolution — do not scale it down to squeeze it in.
- 03
No quiet zone
WhyA barcode needs clear “quiet space” around it; text or the label edge butting against it breaks the read.
FixKeep a clear margin all around the code and do not crowd it with artwork or the trim edge.
- 04
Damage or a curved surface
WhyTears, creases and curved or crushed surfaces distort the bar pattern so the scanner cannot decode it.
FixPlace the label flat on an undamaged, uncurved area of the package.
- 05
Dirt, condensation or faded ink
WhyDust, moisture, or faded direct-thermal print break up the pattern enough to cause a misread.
FixKeep the code clean and dry, and use thermal-transfer (not direct thermal) for anything that must stay scannable over time.
- 06
The wrong scanner for the code
WhyA 1D (linear laser) scanner cannot read a 2D code such as a QR code or Data Matrix.
FixMatch the scanner to the symbology, and confirm the symbology and check digit are correct.
Common questions
Why won’t my barcode scan?
Most often poor contrast — print dark bars on a white background. Also check that the code is large enough, has clear quiet space around it, is flat and undamaged, and that your scanner matches the code type (1D vs 2D).
Why do thermal barcode labels stop scanning over time?
Direct-thermal print fades with heat, light and time, so the contrast drops below what a scanner needs. Use thermal-transfer with a resin ribbon for barcodes that must stay scannable.
Avoid the guesswork
Tell us the surface, the environment and the job, and we’ll spec a material and adhesive that won’t fail — and ship a free sample to prove it.
Materials facts verified by
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