Abstract: Polyamides are stabilized by phenothiazines.

Abstract: Stabilized shaped articles of polyamides are prepared in a simple manner, using a copper-I halide and a molar excess of an alkali or alkaline earth metal halide, by mixing copper(I)-halide and alkali or alkaline earth metal halide with caprolactum, polymerizing the mixture, granulating the melt of the stabilizer concentrate and processing the granules together with the granulated polyamide which is to be stabilized, to give shaped articles.

Abstract: From color density triplets, obtained by the photoelectric point by point scanning of a negative, there are formed an integral density value, a mean density value and a maximum density parameter which are combined by linear combination to form a basic density correction value which modulates the overall density of copies to be produced from the negative. The negative is subdivided into concentric zones, and the more centrally located zones are given a greater weight than the outer zones when the integral density values and the maximum density parameter are being formed. A threshold value is formed and the negative is checked for areas of density greater than the threshold extending up to the margin, and the density values of image points included in such areas are reduced by a certain fraction.

Abstract: A reel of film is printed automatically in a printer to which reel identification, data etc., are fed on a basic data support. Each frame is counted as it passes through the printer and an address consisting of the result of the count and the reel identification data is applied to the print. After visual assessment of the first prints, a correction programme tape is produced with addresses and correction data of the defectively-printed frames and then the printing of these frames is automatically repeated by means of the programme tape. This operation is repeated as required. The programme tape and the film reel are then filed, the first and the repeat prints are sent to the customer who may then compile his reprint order from the addresses shown on the prints. A new programme tape is prepared in the laboratory from the filed programme tape and the reprint order information and the printer is controlled by means of the programme tape in order to carry out the reprint order.