Process, compound, ink and use

摘要

A process for printing an image on a substrate comprising applying to the substrate an ink comprising a compound of Formula (1) or a salt thereof: wherein: R¹ and R² are each independently H or a substituent; each X and Y independently is a substituent; and a and b are each independently 0, 1, 2, 3 or 4. The compounds used in the process have particularly good ozone fastness and are suitable for preparing inks which can be ink jet printed.