A photoreceptor is provided having an electroconductive substrate and a photosensitive layer located overlying the electroconductive substrate, wherein an outermost layer of the photoreceptor contains a binder resin, wherein the binder resin solution satisfies the following relationship 2≦(T0−T400)/C wherein T0 represents a initial transmittance (%) at 400 nm of the binder resin solution; T400 represents a transmittance (%) at 400 nm of the binder resin solution which has been allowed to settle for 400 hours under conditions of 23° C. and 40% RH; and C represents the concentration of the binder resin solution; and an image forming method, an image forming apparatus and a process cartridge including the photoreceptor.