Solvent dye

[1] Solvent dyes are used to color organic solvents, hydrocarbon fuels, waxes, lubricants, plastics, and other hydrocarbon-based nonpolar materials.

Their molecules are typically nonpolar or little polar, and they do not undergo ionization.

They form a colloidal solution in solvents.

They have poor (basic dyes) to good (metal complex based) light fastness.

Solvent dyes are used for gold imitation (and other transparent metallic effects) of metallized polyester films.