John Lenoir

Photographic material containing sulphonic acid group containing disazo dyestuffs

Process for the prevention of darkening and the formation of a sediment in photographic developer solutions

Sulfonic-acid-group containing disazo dyestuffs

Quinoxalines and their use in photographic processes

Dye bleach preparation for the photographic silver dye bleach process

Oil-soluble disazo dyes and their use in color-photographic recording materials for the silver dye bleach process

Azo dyestuffs, methods for their preparation and their use as colouring agents in the silver dyestuff bleaching process

Monoazo dyes containing phosphamic acid diester groups

Disazo dyestuffs and their use in colour-photographic light-sensitive materials for the silver dye bleaching process

Color-photographic recording material for the silver dye bleach process