Good fastness properties owing to the bonding that occurs during dyeing. Most commonly used in dyeing of cellulose like cotton or flax, and cellulosic fibres.
Direct dyes are usually cheap and easily applied, and they can yield bright colours. Direct dyes are used on cotton, paper, leather, wool, silk and nylon.
Acid dyes are ionic in nature. Acid dyes are suitable for wool, silk, polyamide and acrylics and applied from a strongly acidic to neutral pH both.
Solvent dyes are used to color organic solvents, hydrocarbon fuels, waxes, lubricants, plastics, and other hydrocarbon-based nonpolar materials.
