A method for altering fluorescent emissions of particles includes setting the particles in motion and exposing the moving particles to light such that fluorescent intensities of the particles are lessened isotropically and substantially simultaneously. Another method includes measuring fluorescent emissions of particles, determining the measured fluorescent emissions do not collectively fit within a first predetermined range of fluorescent values, and exposing the particles to one or more incidents of light that are configured to cooperatively alter the fluorescent emissions of the particles to be within a second predetermined range of fluorescent values. An embodiment of an apparatus includes a vessel configured to contain a plurality of particles and a means for setting the particles in motion. The apparatus further includes an illumination subsystem configured to direct light toward the vessel and at a spectral window (i.e., wavelength or band of wavelengths) which is configured to isotropically and substantially simultaneously lessen the fluorescent emissions of each of the particles.