Whats the difference between soap dye and soap pigment?
A dye dissolves and becomes inseparable from whatever it is added to — water, alcohol, glycerine. Dye colors are generally brighter than pigments and can change in response to extremes of temperature or pH. They are prone to ‘bleeding’, so they are better suited to single-color pours rather than embedded objects or multi-colored soaps. A pigment does not dissolve, but rather consists of tiny particles which remain suspended in the finished product. Depending on their physical properties, these particles may block light, making clear soaps less transparent–even opaque (white glycerine soap base is pigmented)–or they may reflect light, giving soap a spectral or opalescent appearance. Pigments will not bleed into surrounding areas, so they’re ideal for embedded objects and layering.
