Optical emissions from 50 and 100-g spherical charges were investigated. When the detonation products (DP) expand, they act like a spherical piston-driving a spherical blast wave into the atmosphere. Emissions from this blast wave come from: shock-heated air molecules, detonation-products molecules, combustion products molecules, and carbon particles formed in the detonation wave. Six HEs were studied: TNT, Comp B, PBX-N5, Comp A5, Tritonal, and AP-NM. HE powder was pressed in hemispherical molds. For TNT and Tritonal, a central booster of PBXN-5 and a RP-80 were used to detonate the charges. Experiments were conducted in air versus N2 to control combustion, and at different pressures (1, 0.1 and 0.01 bars) to control emissions from the shock-heated air. Emission histories were measured with an Andor fast kinetics spectrometer. In the visible regime, emission spectra were well fit by a Planckian function-thereby allowing us to compute the evolution of the emission temperature of the fireball. Maximum temperatures in the 1st peak correlate with CJ temperature of the particular explosive. Estimated temperatures fall due to the adiabatic expansion of the fireball gases. The 2nd optical peak was caused by re-heating of the fireball and carbon particles by the shock reflections from the chamber floor.