1. A computer readable medium recording a calibration program, which causes a control device to execute calibration processing of reading as image data a patch sheet output from an image formation device, having a plurality of patch patterns formed as images based on different density-gradation value data for each color, acquiring calorimetric values for each of said patch patterns from the read-out image data, and adjusting the density of said image formation device based on said density-gradation values and said acquired calorimetric values for each of said patch patterns; said program causing said control device to execute: displaying said read-out image data of said patch sheet; detecting and displaying the position of each of said patch patterns in said image data of said patch sheet; and, acquiring the calorimetric values for each said patch pattern based on the displayed patch pattern positions, in response to confirmation input by a user of said displayed patch pattern position.