1. A method of setting image processing conditions, comprising: a first step of specifying at least one point to be corrected in image data and specifying finishing requirements to be met at said specified point; a second step of processing the image data at said specified point under predetermined image processing conditions to obtain processed image data; and a third step of comparing said processed image data with target processed data and correcting said image processing conditions based on a result of said comparison, said target processed data satisfying said finishing requirements, wherein said comparison of said processed image data with said target processed data in said third step is effected by using the following evaluation function f: ##EQU3## where j: integer designating one of said finishing requirements, m: number of said finishing requirements, i: integer designating said at least one specified point, n: number of said specified points, k.sub.j, w.sub.ij : weighting factors, y.sub.ij : non-corrected processed image data at i-th said specified point, y.sub.ijo : target processed data at i-th said specified point, and F: function having (y.sub.ij -y.sub.ijo) as a variable.