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Publication of BE716882ApublicationCriticalpatent/BE716882A/xx
B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
B41M5/00—Duplicating or marking methods; Sheet materials for use therein
B41M5/124—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
B41M5/132—Chemical colour-forming components; Additives or binders therefor
B41M5/155—Colour-developing components, e.g. acidic compounds; Additives or binders therefor; Layers containing such colour-developing components, additives or binders
B41M5/1555—Inorganic mineral developers, e.g. clays