An electronic device may be provided with a display and other electrical components. The display may be covered with a display cover layer. A rear housing member, the display cover layer, and other structures in the device may be formed from a transparent member. Transparent members in the device may be covered with layers such as layers of ink. The ink may have a polymer with colorant such as dye or pigment. Light-scattering particles such as inorganic dielectric particles may be incorporated into the polymer. The inorganic dielectric particles may have cores formed from materials such as titanium dioxide and coatings that help prevent discoloration of the titanium dioxide and degradation of surrounding polymer when the inorganic dielectric particles are exposed to ultraviolet light.