Abstract: A method and an apparatus for exposing light-sensitive materials, including a first light beam conducted from a light source with the wavelength &lgr;1 to a first exposure point on the light-sensitive material via an optical system. This system has at least one input end and one output end as well as at least one reflecting or transmitting rotating optical element arranged relatively to the optical output end, wherein at least one additional light source generates an additional light beam with a wavelength &lgr;x which is different from &lgr;1.

Abstract: A medium is retained in the predetermined mutual spaced relation in a gap between two plane faces on respective bodies. The bodies are mutually displaceable in a direction substantially perpendicular to the gap and biassed in the direction of displacement. One of the bodies is connected with a compressed air source providing through a plurality of outlets in the plane face of the respective body an air cushion between the face and the medium.

Abstract: A method and apparatus for the illumination of points on a medium by illuminating a plurality of perforations that are arranged parallel to the medium with light having a center wavelength .lambda.. The perforations have a cross-section so as to provide for each perforation a diverging bundle of rays formed by defracting the light. The medium is positioned from the perforations at substantially the transition of the diverging bundle of rays between the Fresnel region and the Fraunhofer region.