The radiation characteristics of a high-current hydrogen thyratron plasma have been modeled in order to study this aspect of the physics of the conductive phase of thyratron operation. The intensities and radiative energy efficiencies of the atomic and molecular systems have been calculated in detail. A model is developed that is useful for studies of photoemission. For discharge parameters T_e ≈ 1 eV, ionization fraction of ∼10⁻² and background density of 10¹⁶ cm⁻³, the total power of the emitted radiation is estimated to be of the order of 5% of the total input power during the conductive phase.