1.1 Dyeing auxiliaries Auxiliaries are compounds which are not an integral part of the dyeing process but by adding them to the dye bath the dyeing can be improved. The main functions of auxiliaries are to prepare or improve the substrate in readiness for colorants (by wetting, providing sorption sites, improving or resisting the migration of dyes), to stabilize the application media (by improving dye solubility, stabilizing a dispersion or solution), to protect or modify the substrate (by creating or resisting dyeability, protecting against the effects of temperature and other processing conditions), to improve the dyes fastness (by various after-treatments) and to enhance the properties of laundering formulation. The main ranges of dyeing auxiliaries are: crease inhibitors, wetting agents, defoamers, diffusion accelerants, carriers, dispersing agents, dye-protective agents, fibre-protective agents, fixing agents, levelling agents, migration-inhibiting agents, pH regulators, buffers, sequestering agents, UV absorbers, fibre stabilizers, UV protective agents and wash-off agents.