A region for quantization having a value lower than the value B is assumed as having little influence by Bk data on the pixels in this region. Thus, in order to prioritize the optimization of the granularity at the start of the input of GY data, the LUT having a combination of GY and gy as an input as an input is used to perform separation quantization. On the other hand, since a region having a value equal to or higher than the value B requires the use of Bk data, the LUT having only a combination of Bk and GY as an input as an input is used to perform quantization. As a result, the number of types of pieces of ink data referencing the table can be 2, thus suppressing an increase in the table size.