An image processing apparatus includes a color material layer forming unit and a proportion controller. The color material layer forming unit forms on a printing medium a first metallic color material layer including a color material having metallic particles, one or more process color material layers including color materials of one or more process colors, and a second metallic color material layer including a color material having metallic particles so that the first metallic color material layer, the one or more process color material layers, and the second metallic color material layer are stacked on the printing medium in this order. The proportion controller executes first control to increase a proportion of the second metallic color material layer with respect to the first metallic color material layer when a total amount of the color materials of the one or more process colors exceeds a predetermined value.