An image processing apparatus for converting color data into gray data extracts an object included in the color data in a page, and determines, based on color information and position information on a first object and a second object extracted, whether at least one of the first object and the second object is to be a target of conversion of a color value of the color data into a gray value with improved discriminability. The image processing apparatus controls to convert the color value of the object into a gray value by a conversion targeting all color values, or into a gray value with the improved discriminability, based on the determination whether or not to be the target of conversion.