To a greater or lesser extent, all alkaline-earth oxide crystals contain hydrogen. Thermochemical reduction (TCR) of MgO and CaO crystals at high temperatures (˜2000K) and high pressures (4 to 7 atmospheres) of the metallic cation vapor (Mg and Ca respectively) results in a stoichiometric deficiency of oxygen ions, creating F centers (oxygen vacancies each with two electrons) and H− ions (protons in the anion sublattice, each occupied by two electrons). The positively-charged H− ions serve as traps for electrons excited from the F centers. Steady-state photo-excitation of the F absorption band results in F luminescence which typically extends to several minutes. This photoluminescence is detrimental for certain applications, such as tunable lasers. We have been able to reduce the hydrogen concentration prior to TCR of MgO and during TCR of CaO. The result is that the oxygen vacancies are predominantly in the one-electron F+ charge state. In contrast to the F luminescence, the decay of the F+ luminescence does not exhibit long phosphorescence. The prevalence of the F+ over the F state is found to be a function not only of the hydrogen concentration but also the severity of the thermochemical reduction.