The threshold energy and the time of yielding the first laser pulse as a function of absorber concentration are experimentally determined. In cooperation with the coupled rate equations of the system, the effect of absorber concentration on the performance of a pulsed laser system is studied. The experimental data are processed in such a way to allow a direct determination of pumping dynamics through the parametersntandtp, and to measure the relative absorption cross section of cryptocyanine and ruby by observing the laser output only.