Short answer
Conventional black packaging is coloured with carbon black, which absorbs the near-infrared light that sorting machines use to identify plastics, so the pack is not recognised and usually ends up as residue. A black pack can be made sortable with a black colourant that contains no carbon black, but results depend on the pigment, the polymer and whether sorting lines are tuned to detect it.
Black trays and tubs are popular because they hide food residue and cooking juices, make fresh food look vivid by contrast, suggest premium quality in some categories, and — for plastics made from mixed recyclate — hide the muddy colour of the material itself. Carbon black is the cheapest and most opaque way to achieve that black, and it is often already present in recycled content. Those are real advantages, which is why simply banning black from packs is not how most design guidance approaches it; it targets the pigment rather than the colour.
Near-infrared sorters identify a polymer from the pattern of light its chemical bonds reflect. Carbon black absorbs across the visible and the near infrared, so a carbon-black tray gives almost no reflected signal — a Fraunhofer paper describes it as all light absorbed and no detectable signal to evaluate. WRAP's work in the UK found that carbon-black packaging is therefore not sorted by the NIR equipment widely used in recycling and ends up as residue for landfill or incineration. Recycler guidance in North America tests any dark pack below set lightness and NIR-reflectance thresholds for sortability instead of assuming it will be recognised.
An NIR-detectable black is a colourant formulation without carbon black that absorbs visible light, so the pack still looks black, while letting near-infrared light through or reflecting it so the polymer's fingerprint stays readable. WRAP-commissioned development work and subsequent commercial masterbatches showed this is practical; UK Plastics Pact members were asked to move to detectable black pigments. WRAP also notes that sorting black material raises no issue for polyolefins but that black PET brings questions about PET end markets, and that sorting equipment may need fine-tuning to pick up the new pigments reliably.
The design options, in rough order of recyclability, are: a non-black colour that achieves the same function (dark green, dark blue or grey can also hide residue); a detectable black, tested for sortation; or conventional carbon black accepted as not recognised by NIR. For PET trays, European guidance for clear PET lists carbon black as not compatible, and APR notes that markets for black PET remain limited even when it sorts. For HDPE, RecyClass guidance for the natural-and-white stream lists black and carbon black as not compatible, which is a reminder that colour decides which stream a pack joins, not just whether it is detected.
| Appearance choice | NIR sorter result | Recyclate colour | Trade-off |
|---|---|---|---|
| Carbon-black tray | Typically not identified | Lost to residue | Cheapest, most opaque black |
| NIR-detectable black | Identified if line is tuned | Dark recyclate | Pigment cost; test sortation |
| Very dark non-black colour | Depends on pigment; test | Dark recyclate | Looks less 'premium black' |
| Mid-tone colour (grey, dark green) | Identified | Coloured fraction | Hides residue less well |
Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.
FactStrong evidence
Carbon black absorbs light across the near-infrared range used by plastic sorting machines, so carbon-black items return no usable signal for polymer identification.
FactModerate evidence· United Kingdom
Conventional carbon-black plastic packaging is not sorted by widely used NIR equipment and commonly ends up as residue; NIR-detectable black pigments that avoid carbon black allow sorting, although equipment may need fine-tuning.
Source: Recyclability of black plastic packaging; Black plastic packaging hub
FactModerate evidence
Commercial NIR-detectable black masterbatches for packaging were available by 2018, following WRAP-commissioned development work.
ConventionModerate evidence· North America
Recycler guidance treats black or dark PET with low lightness or NIR reflectance as requiring a sortation test and notes that markets for black PET containers remain limited.
Source: APR Design Guide for Plastics Recyclability: PET Rigid
Reviewed 29 September 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.