Separating indigo assay from relative tinting strength in a dyeing trial

Trial design and interpretation

Dye swatches from the same fabric lot under identical conditions with the standard and candidate. Retain swatches from corresponding locations. When depth of shade differs, check the commercial dye assay and the basis of relative color strength.

Recording Dye content

Dye content (% by mass): ENVO published powder grade ≥94.0. Accept powder and granulated material separately. Specify method and dry or as-received basis. Tinting strength: use the agreed method. Use cotton yarn from the same lot and identical reduction conditions.

Why does the same product weight give a different depth of shade?

Correct for actual dye content and identify powder or granules. Run the samples in the same dyebath conditions. Cotton yarn exhaust dyeing: At the same yarn count and process conditions, compare shade depth, levelness and lot-to-lot color difference.

What to record

• Fabric lot
• Commercial assay
• Reference sample ID
• Color difference and shade depth

Technical references

• ENVO · Indigo Blue catalogue and product information ↗

Products and processes