A color conversion method includes: a step (a) of obtaining paper white information including a spectral reflectance and a scanner response value of a paper white portion of a document, a step (b) of searching for a registered scanner profile corresponding to paper white information the same as or similar to the paper white information, from a plurality of registered scanner profiles for paper types, and a step (c) of determining whether a new scanner profile needs to be created corresponding to the paper white information obtained in the step (a), according to a result of searching in the step (b).