We present a detailed analysis of the plasma conditions required to optimize gain in two proposed x‐ray lasing schemes using resonant photo‐pumping. In one proposed configuration, the Si XIII line 1s2‐1s2p1Pat 6.650 A˚ pumps Al XII 1s2−1s3p1Pat 6.635 A˚, inverting the Al XIIn= 3 andn= 2 levels which are separated by 44 A˚. A similar approach which utilizes the Na X 1s2‐1s2p1Pline at 11.00 A˚ would invert then= 4, 3, and 2 levels of Ne IX. Conditions in the pumped neon and aluminum plasmas, and in the pumping silicon plasma, are calculated using a multistage, multilevel atomic model with multifrequency radiation transport. For modeling the pumping sodium line we have inferred the intensity from a spectrum of a neon filled, laser‐imploded glass microballoon containing sodium impurities obtained at Rochester. The pump line intensities calculated for Si and inferred for Na are equivalent to blackbodies of 252 and 227 eV, respectively. It is found that peak gain for the 3‐2 lines of about 100 cm−1occurs at ion densities of 1020cm−3and 4×1020cm−3in the pumped neon and aluminum plasmas, respectively. Temperatures required to maximize gain in the pumped plasmas are found to be 50 and 100 eV, for neon and aluminum, respectively. Finally, since the silicon and aluminum lines are slightly off resonance, we have investigated the effect of streaming the plasmas toward each other at various velocities to offset some or all of the wavelength difference. It is found that a streaming velocity of 6.8×107cm sec−1—fully offsetting the wavelength difference—will approximately triple the achieved gain compared to the zero velocity case. Lesser increases in gain occur with partial velocity offsets.