Abstract: A measuring light source includes a hollow body having a diffusely reflective inner surface. Formed in the hollow body are a concave, concave mirror-shaped illumination space, a tubular light shaping space, and a concave, concave mirror-shaped light exit space, which have a shared axis. A light source for generating light is at least partially situated in the illumination space. The light exit space has a light exit. The illumination space and the light exit space with their concave mirror shapes are situated opposite one another and are connected by the tubular light shaping space. A diffusely reflecting reflective disk for reflecting the light, reflected from the inner surface of the hollow body situated in the light exit space, through the light exit to outside the hollow body is situated in the hollow body.

Abstract: A measuring light source includes a hollow body having a diffusely reflective inner surface. Formed in the hollow body are a concave, concave mirror-shaped illumination space, a tubular light shaping space, and a concave, concave mirror-shaped light exit space, which have a shared axis. A light source for generating light is at least partially situated in the illumination space. The light exit space has a light exit. The illumination space and the light exit space with their concave mirror shapes are situated opposite one another and are connected by the tubular light shaping space. A diffusely reflecting reflective disk for reflecting the light, reflected from the inner surface of the hollow body situated in the light exit space, through the light exit to outside the hollow body is situated in the hollow body.

Abstract: The invention relates to an arrangement for measuring the reflectivity of the direct or scattered reflection of a sample (8), having a light source for separately lighting the sample (8) and of comparative surfaces. The arrangement comprises, in addition to the light source, preferably a reflector lamp (2), —a white standard (6), a black standard (7), and the surface of the sample (8) for embodying a measurement surface, wherein the exchange of the white standard (6), the black standard (7) and the sample (8) is provided in a prescribed sequence relative to each other, —means for measuring the intensity of the light reflected from an internal white surface (10) and for measuring the intensity of the light reflected from each measuring surface, and—an evaluation circuit designed for registering the measured intensity values and for linking the same mathematically to the reflectivity.