1. A color matching method in which, when color reproduction ranges of a first device and a second device differ, image data within a color reproduction range of said first device is converted using a conversion parameter into image data within a color reproduction range of said second device, comprising the steps of: obtaining data related to a specific color of said first device and data related to a specific color of said second device in a prescribed color space; and determining said conversion parameter by estimating the color reproduction range of said first device and the color reproduction range of said second device based on the respective data related to the specific color that are obtained.