A process for preparing coated nanoscale quinacridone pigment particles,
includes providing a first solution containing a surface additive
compound in an acid; adding a quinacridone pigment precursor or crude
quinacridone pigment into the first solution and causing the surface
additive compound to coat formed nanoscale quinacridone pigment
particles; and adding the first solution and coated nanoscale
quinacridone pigment particles into a second solution containing
deionized water to form a third solution and to precipitate the coated
nanoscale quinacridone pigment particles; wherein the surface additive
compound is a rosin compound.