Brewster cut CdSe crystals pumped by the P1(8) line of an HF laser were used to amplify optical signals at 16 μm. The source of the signals was a CdSe OPO pumped by the P2(7) line from the same laser. The configuration of both pump beams was such that flat radial intensity profiles were produced at the respective crystals, eliminating the need for confocal focusing. The gain bandwidth was measured and found to be in reasonable agreement with theory. The second order nonlinear susceptibility was measured for the first time at 16 μm and found in fair agreement with values determined at shorter wavelengths scaled to 16 μm through Miller's Δ.