The apparatus is for measuring at least one of color and trash in a fiber sample. A light emitting diode light source generates an incident light that is directed toward the fiber sample, and reflected by the fiber sample, thereby producing a reflected light. A sensor receives the reflected light and produces a signal. A controller controls the light source and the sensor, and at least one of receives and adjusts the signal. At least one of the incident light, the reflected light and the signal is conditioned to compensate for differences between the light emitting diode light source and a xenon light source. Thus, drawbacks of the xenon light source used to date can be avoided.