Sorting dark packaging

 

Sorting dark packaging

Why does dark-coloured packaging pose a challenge for recycling?

Dark-coloured packaging (black, dark blue, dark green, brown, charcoal grey, etc.) is widely used across many sectors.

However, not all dark packaging is detected in the same way at sorting centres.

Certain colouring agents, particularly those containing carbon black, absorb the near-infrared radiation used by optical sorting equipment. As a result, the packaging is not correctly identified and may not be directed to the appropriate recycling stream.

On the other hand, there are now innovative dark colourants capable of being detected by optical sorting equipment, thereby making it possible to combine dark colour with recyclability.

The dark colour of a packaging item does not therefore automatically mean that it will be incorrectly sorted at a sorting centre: it all depends on the colourant used.

COTREP, a long-standing player in this field

In response to this issue, COTREP launched a project in 2019 aimed at identifying solutions compatible with the sorting and recycling of rigid plastic packaging.

This work led to the establishment of a specific testing protocol to assess the detectability of dark colourants under conditions representative of French sorting centres.

Where tests demonstrated satisfactory detection, a COTREP Technical Opinion was issued.

This work has contributed to the development of the range of detectable dark colourants available on the market and to reducing the presence of packaging containing undetectable pigments. Between 2021 and 2024, the marketing of packaging containing carbon black has thus fallen by 40 %.

Transfer of the subject to COCET

Since 2025, the monitoring of dark packaging and, more broadly, the study of packaging behaviour in sorting centres has been carried out by COCET.

COCET is now responsible for:

  • the dark packaging protocol
  • work relating to dark packaging
  • the issuing of technical opinions
  • the positive list of approved colourants

All resources previously published by COTREP on dark packaging (protocol and Technical Opinions) will shortly be transferred to the COCET website (https://www.cocet.fr/etude-technique/). Until then, they remain available on the COTREP website ( https://www.cotrep.fr/etude-technique/)

For any new requests for sorting tests on dark packaging, please contact COCET directly.