Direct thermal or thermal transfer? How to tell your labels apart
A thermal printer only works with the right labels, loaded the right way round. It takes two minutes to check, without printing anything.
The scratch test
Scratch the label surface quickly with your fingernail, or rub it with the edge of a coin.
- A grey or black mark appears: it is direct thermal paper, and that side must face the printhead.
- Nothing appears on either side: the label is for thermal transfer and only prints with an ink ribbon.
The friction heats the sensitive coating locally, just as the printhead does. It is also why direct thermal labels can mark when they rub inside a bag or box.
Wound outside or inside?
On a roll, labels are either on the outside of the spiral or on the inside, facing the core. Desktop printers usually expect labels wound outside. If your roll is wound inside and the label comes out blank, the thermal side isn’t touching the head: check the printer’s loading diagram.
Direct thermal vs thermal transfer
| Direct thermal | Thermal transfer | |
|---|---|---|
| How it works | The head darkens a heat-sensitive coating on the paper | The head melts ink from a ribbon onto the label |
| Ribbon | No | Yes |
| Print life | Weeks to a few years, depending on paper and storage | Several years |
| Resistance to heat, sunlight, rubbing | Low to medium | Good to very good |
| Typical use | Shipping labels, receipts, short-life labels | Product labels, long-term stock, outdoor, industrial |
Some printers do both: direct thermal without a ribbon, thermal transfer with one. The setting in the driver must match the media.
Top-coated thermal labels
Direct thermal labels come with or without a protective top coat. The coating protects the print from moisture, grease and some plastics, and slows yellowing. For parcels in transit for a few days, standard paper is fine. For product labels, frozen food or records to keep, choose top-coated labels.
If the print fades
Direct thermal paper fades in light and darkens with heat. Keep rolls in their packaging, somewhere cool and out of the sun, and use them within a year. If the print fades within weeks, you need top-coated labels or thermal transfer. Other symptoms are covered on the troubleshooting page.