Abstract: The subject of the present invention is a solid material in the form of a microperforated sheet transparent to light of wavelengths in the visible and infrared, characterized in that the mean distance between two immediately neighbouring perforations is at least 5, and preferably 7 .mu.m, and is so over each face of the material. Preferably, the mean angle of inclination of the perforations through the thickness of the material is less than 10.degree., even 5.degree.. In a particular embodiment, the material is a membrane produced from a flexible polymer film with a thickness lying between 0.1 and 100 .mu.m, more generally between 5 and 50 .mu.m, and the perforation diameters lying between 0.01 and 15 .mu.m. The membranes obtained according to the invention are particularly useful as support membranes for viewing in an optical microscope or in infrared spectroscopy. They may also be used as filter membranes or, amongst other applications, as a support for cell culture.