A cosmetic agent for dyeing keratin fibers, in particular human hair, includes at least one special non-ionic linear silicone polymer and at least one oxidation dye pre product and/or a direct dye. The use of the at least one non-ionic linear silicone polymer leads to an improved colorfulness and/or depth of shades. A corresponding packaging unit (kit of parts) and a method for dyeing keratin fibers both include the cosmetic agent. The cosmetic agent and packaging unit including the same are used for increasing the colorfulness and/or depth of shades.
