Photophoresis with plane waves and spherical absorbers is traditionally investigated by considering monochromatic radiation. The asymmetry factor, which is proportional to the photophoretic force, can be expressed in using the Mie theory in terms of an infinite sum of terms depending on the wavelength of the impinging light. Here, we analyze an extension of the photophoresis problem for a polychromatic uniform optical field. Such an analysis demands the introduction of a spectrum which describes the weight of each plane wave for the total, polychromatic field. We expect that this work can find applications or pave the way for more advanced investigations in diverse areas of physics and engineering such as optical levitation, optical trap displays and spectroscopy.