Abstract: Methods are disclosed for simulating custom hair color results, for selecting a resulting custom hair color from among possible custom hair color results, and for formulating custom hair coloring compositions which impart to hair such custom hair color results.

Abstract: A service trolley (1) having a pedestal (2) on which rollers (3) are provided for moving the service trolley (1) and having at least one holding surface (4, 5, 23, 25) on a support beam (6) is provided for use in a hair salon. In order to be able to carry out a dust-free production of hair coloring right next to the hairdresser's customer, it is proposed that a holding surface (4) has a device (7) for holding granulate (8) for hair coloring purposes. The granulate (8) can be dosed in a simple manner and also can still be used after longer periods of storage.

Abstract: A device (1) comprises a reservoir (2), preferably having a transparent wall (8), for holding a flowable product (3) and a dispensing head (4) for discharging the product (3). The dispensing head (4) is joined to the reservoir (2) via a coupling (5), especially a threaded coupling. Provided on dispensing head (4) is an actuator device (6) for opening and closing the dispensing head (4) as desired in order to dispense product accordingly from a discharge opening (18). In order to prevent erroneous refilling with product when an empty reservoir (2) is replaced with a full reservoir (2), especially when there is a set of reservoirs (2) having different products (3) for coloring hair, it is proposed that the product (3) be a powdered or granulate hair dye and that the surface of the dispensing head (4) or the actuator device (6) have an information surface (7) that is to be assigned to the product (3). The powder or granulate form thus serves to ensure recognition of the color of the product (3).