A lighting device in a motor vehicle includes a number of illumination devices, which each generate colored light via a plurality of color channels. The illumination devices can be controlled using an electronic control unit. An illumination state of a respective illumination device can be adjusted by color component values and a brightness end value for all color channels. The electronic control unit calculates a color value from the illumination state to be adjusted for each color channel based on the color component value of the respective color channel and the brightness value. The color value is supplied to the respective illumination device. The electronic control unit processes a brightness threshold value used during a dimming-down/dimming-up process for switching-off/on the respective illumination device. The brightness threshold value is determined by the electronic control unit and increases as the lowest color component value decreases.