This paper is dedicated to development and application of an algorithm allowing determining an accurate actual value of the plasma background radiation under the analytic element line using standard data obtained from emission spectrometer registration system. A unique technique has been developed that allows calibrating spectrometers in the range of small concentration of impurities with two standard samples, which is very relevant for analysis of metals and alloys, powdered samples, ultrapure materials. The paper demonstrates efficiency of this technique when applied to series-produced emission spectrometers manufactured in Russia.