FORMULAIRE ENDUIT AU PREALABLE AVEC DES COMPOSANTS REACTIONNELS POUR COULEURS, CAPABLES DE REAGIR D'UNE FACON MULTICOLORE

摘要

For printed forms and the like having latent print images which have been printed with colour formers of various reaction colour, where all the colour formers used react with the same reactant visibly to form a colour, particularly suitable reactants have been found to be either phenolic compounds or alkaline substances in the pH range from 8.2 to 10.5.