The possibilities of isophotometry methods for the analysis of low-intensity spectral lines are considered. The purpose of spectrum isophotometry is to detect spectral lines and zones of a low intensity level. The proposed method serves as an alternative to the traditional methods of registering spectrum lines that use photographing the spectrum on the image receiver, which allows obtaining information on the distribution of the relative intensity of the spectrum in the range of two orders of magnitude. The isophotometry of the point spread function makes it possible to obtain a range of relative illumination differences in the image up to 10–4 – 10–5. The same possibilities open up with spectrum isophotometry. The basics of innovative methods of isophotometry of radiation and fields are briefly reviewed. It is noted that the main advantage of the spectrum isophotometry method is the possibility of detecting new spectral lines that cannot be detected by traditional methods. The method effectiveness and the scope of its application are described.