The specification and drawings present a new apparatus such as a halogen incandescent lamp is presented herein, the apparatus comprising a light source such as a light-generating element made of tungsten, configured to generate a visible light such as white light having chromaticity coordinates of the light source in a clear center in a color space, and a component such as light-transmissive envelope, enclosing the light source and comprising a coating with a compound comprising elements of neodymium and fluorine and configured to provide a desired light spectrum by filtering the generated visible light using the compound, where the desired light spectrum having chromaticity coordinates in the color space being shifted from the clear center below the black-body locus and outside of a four-step MacAdam ellipse of the light source to meet a predefined requirement for a modified spectrum lamp.