To provide a treated substrate having a hydrophilic region and a water repellent region, of which contrast is high on its surface. Further, to provide a process for producing a treated substrate, wherein a specific equipment, light having a high energy or light irradiation for a long time is not required, and the treated substrate can be produced with a low amount of light for a short time.
A treated substrate having a hydrophilic region and a water repellent region on a surface of a substrate, characterized in that the water repellent region is made of a water repellent film formed by curing the composition (A) comprising a photopolymerization initiator and a compound (a) having at least one (meth)acryloyl group, and a water repellent moiety and having a film thickness of from 0.1 to 100 nm. A process for producing a treated substrate, characterized by using a hydrophilic substrate or carrying out a hydrophilic treatment on a surface of a substrate to make the surface hydrophilic, then forming a film containing the composition (A) on the surface, then forming a water repellent film having a film thickness of from 0.1 to 100 nm by irradiating light on a part of the film surface to cure the composition (A) and then removing an uncured composition (A) present on the surface of the substrate in order to expose the hydrophilic surface.