How dark is too dark?

The European glass recycling chain is considered one of the most developed material cycles in the pack-aging sector. Container glass can be recycled almost indefinitely in a closed cycle without any significant loss of quality. However, for this to happen, glass fragments must be reliably recognized as glass in the processing plants and not incorrectly discharged as impurities. The "Study on the glass transmittance of opaque glass packaging", which Stazione Sperimentale del Vetro carried out on behalf of FEVE, analyzes the light transmission at which dark, thick-walled glass is no longer reliably identified as glass by optical sorting systems in European glass breakage processing plants.