An image forming method for an image forming apparatus having a fixing rotator and a pressure rotator opposite the fixing rotator includes transferring white toner and color toner onto a surface of a metallic sheet. The metallic sheet has a thermal conductivity of 0.34 W/m·K or less as measured by hot-wire method. The transferring process forms an unfixed color toner layer layered on an unfixed white toner layer on the metallic sheet. Further, the method includes conveying the metallic sheet, with the surface on which the white toner layer and the color toner layer being transferred facing the fixing rotator, between the fixing rotator heated and the pressure rotator to fix the white toner layer and the color toner layer onto the metallic sheet.