The relationship between gas concentration and laser power output is examined for mixed noble gas ion lasers. Specifically, a parametric study was carried out on argon‐krypton lasers with cw three‐color power outputs of over 3 W, balanced to give white light as defined by CIE illuminant C. It is found that provided total gas density is maintained constant, argon and krypton gases may be mixed at will in ion laser discharges to obtain the required output balance, implying a mutual compatibility of discharge conditions for argon and krypton lasers. This compatibility is explained by showing that at the same gas densitites of argon or krypton, expected electron temperatures are approximately the same. Under these conditions, excitation rates of laser levels are proportional to the fractional gas concentrations.