Image processing apparatus to improve dot dispersibility with n-gradation multi-valued data, image processing method, and storage medium

An image processing apparatus comprising:

• a determination unit configured to determine whether a difference between a maximum value and a minimum value of pixel values of a plurality of pixels in a unit region of interest in N-gradation multi-valued data, where N≥4, representing the pixel values of the plurality of pixels is less than a determination threshold value;
• and
• a generation unit configured to generate M-gradation quantization data represented by an M-gradation quantization value, where 3≤M<N, based on the N-gradation multi-valued data and the determination by the determination unit,
• wherein in a case where the determination unit determines that the difference is less than the determination threshold value, the generation unit generates the M-gradation quantization data so that each of the plurality of pixels corresponding to the unit region has a value that is one of two consecutive values of the M-gradation quantization values in the generated M-gradation quantization data.