Abstract: Concentrated leuco indigo solutions useful for dyeing cellulosic textile material consist essentially of from 25 to 55% by weight of leuco indigo in the form of the leuco indigo salt, an amount which is essentially stoichiometrically sufficient to convert the leuco indigo into the neutral leuco indigo salt of a mixture of at least two alkali metal hydroxides wherein none of the alkali metal hydroxides accounts for more than 70 mol %, and water.

Abstract: Granules comprising as essential constituents a leuco vat dye, an alkali metal hydroxide and a mixture of from 10 to 100% by weight of an .alpha.-hydroxy-C.sub.1 -C.sub.4 -alkylsulfinic acid, one of its salts or derivatives and from 0 to 90% by weight of hydrosulfite as reductant, are prepared and used for dyeing cellulosic textile material.

Abstract: A guard for contrarotatable cylinders of a printing press includes a finger protective element disposable adjacent cylindrical surfaces of the cylinder for guarding a nip between the cylinders in vicinity of a danger zone, the finger protective element being in fixed position and having at least one switch sensor disposed in the region of the cylinder nip.

Abstract: Granular leuco vat-dye preparations containing, as essential components, leuco vat-dye, reducing agents and alkaline metal hydroxide, and the production of said preparations and their use in dyeing cellulose-containing textile materials.

Abstract: A safety device on a printing press, including at least one switch, a mechanical protective device changeable in position for operating the switch, the switch being fastened to a frame of the printing press so as to be adjustable in position and releasable from the frame, and connecting elements by the aid of which the switch is firmly seated on a base plate and held immovably on the frame, includes an intermediate plate formed of a relatively soft material disposed between respective fastening surfaces of the base plate and the frame, the intermediate plate being secured in position against movement in a direction parallel to the fastening surfaces, the fastening surface of the base plate having at least one projection formed of a material relatively harder than the relatively soft material of the intermediate plate, the projection being pressable into the relatively soft material of the intermediate plate by holding forces exerted by the connecting elements perpendicularly to the respective fastening surfac

Abstract: A process for purifying indigo comprises extracting an aqueous leuco indigo alkali metal salt solution with an inert solvent under oxygen-excluding conditions and conventionally regenerating the indigo by oxidation.