The invention discloses a method for reduction of autofluorescence in biological samples, comprising the steps of: a) providing a biological microscopy sample; b) irradiating the sample with visible light, wherein the visible light has a spectrum such that at least 50% of the light intensity emanates from a narrow wavelength interval within the visible range. The invention also discloses a method for autofluorescence reduction with triplet sensitizers irradiated with visible light.