Dyes: Characteristics
Shade, strength and fastness: how buyers grade a dye
What this tab covers The physical and chemical properties that set its grade, price and uses, with the commercial grades and the standards that define them.Buyers judge dyes by shade, strength (relative to a standard), fastness to washing, light and rubbing, fixation rate, solubility or dispersion stability, and compliance with restricted-substance lists. Strength is adjusted with salt or dispersant, so price per kilogram only makes sense at a stated strength.
Properties that matter commercially
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Strength | stated as% against a standard (e.g. 100%, 150%, 200%) (indicative) | price comparisons and dosing | indicative |
| Fixation rate (reactive dyes) | about 70-90% (indicative) | unfixed dye ends up in effluent and needs extra washing | indicative |
| Fastness ratings | ISO 105 grey scale 1-5 (washing), blue wool 1-8 (light) (indicative) | brand specifications | indicative |
| Restricted substances | below ZDHC MRSL limits; free of 22+ banned aromatic amines (indicative) | access to brand supply chains | ZDHC MRSL 3.1 (via Faxian Gongchang 2026); indicative |
Commercial grades
- Disperse (low, medium, high energy)
- Reactive (VS, MCT, bifunctional)
- Vat (indigo, anthraquinone vats)
- Sulphur (black, blue)
- Acid and metal-complex
- Direct
- Basic (cationic)
- Digital inkjet dye inks
- Food and cosmetic colours