An image processing apparatus includes an acquiring unit configured to acquire a first amount of a transparent toner for use in 2-pass printing in which a color toner is fixed on a recording medium and then the transparent toner is fixed, a change-amount acquiring unit configured to acquire a first amount of change in lightness between an image after the color toner is fixed to the recording medium and an image after the 2-pass printing is performed on the recording medium using the first amount of the transparent toner, and a setting unit configured to set a second amount of the transparent toner for use in 1-pass printing such that a difference between the first amount of change in lightness and a second amount of change in lightness is equal to or smaller than a threshold, the second amount of change in lightness being an amount of change in lightness between the image after the color toner is fixed to the recording medium and a 1-pass printing image after the color toner and the second amount of the transparent toner are fixed to the recording medium.