Protection against nanosecond laser pulses with self-activating materials is soon a reality. This report treats a measurement method of optical power limiting of microsecond laser pulses. The limiting properties of porphyrins, naphtalocyanine, tiophen, alcynylplatnum(II), carbon black suspension (CBS), C60 and iodine were analyzed at the wavelength 582nm. The best clamping of µs-laser was attained at approx1 µJ for the materials CBS and SiNc (50% photopic transmission). Further research is needed to develop new materials that can limit laser light of different pulse lengths.