Commercially Available Diarylide Yellow and Orange Pigments

4 Commercially Available Diarylide Yellow and Orange Pigments 

12 has a medium yellow hue, which is used to a large extent in letterpress and offset printing inks as the yellow component in three and four color printing. To adjust P.Y.12 to the standard yellow of the European standard (Sec. 1.8.1.1), the hue may be shaded with traces of a redder component, such as one of the orange pigments P.O.13 or 34. No such shading is necessary for P.Y.12 to match the yellow on the Kodak scale. 

Colour Index Constitution Numbers 21107 (P.Y.124) and 21107 1 (P.Y.87) are misleading, since both pigments exhibit different chemical structures. 

12 is a typical diarylide yellow pigment in that its prints are fast to clear lacquer overcoating, which is used to protect tin prints against scratching and scrubbing. They are also fast to sterilization (Sec. 1.6.2.3), which is one of the major requirements of an ink to be printed on food cans. 

12 types are used in packaging gravure and flexographic inks for their reasonable price, but they can also be utilized in aqueous printing inks, provided they are sufficiently fast to light. They cannot be applied as decorative printing inks to laminated paper. 

---