Abstract: The invention relates to a measuring arrangement for measuring the density of a product by means of microwaves. The measuring arrangement comprises a first microwave resonator, from which, in operation, microwaves enter a product area, and a device for compensating for environmental influences and disturbance variables affecting the measuring signal of the first microwave resonator. According to the invention, the compensation device comprises a second microwave resonator, which is shielded towards the product area with respect to microwave radiation.

Abstract: A light-tight packaging entity includes rigid side covers (4) and a flexible light-tight covering film (3), which envelops the curved surface of a file roll (1) and is shrunk onto outer edges (5) of the side covers (4) to keep incident light away. This packaging entity makes it possible to achieve reliable protection from light with a packaging entity of small size, ensures unimpeded rewinding of the film, and enables the light-sensitive material to be handled in daylight. The present packaging entity is space-saving, capable of being rewound, leaves no packaging residues in the processing device after opening and unrolling have taken place, and in addition is simple and cost-effective.