1. An endoscopic system that processes a color image data of a subject from an imager mounted on an endoscope and records the processed image data in an image recorder/display unit, the endoscopic system comprising: a storage that stores matrix data for forming a spectral image; and a spectral-image forming circuit that is capable of forming (i) a spectral image in an arbitrarily-selected wavelength band according to a matrix operation of the matrix data in the storage and the color image data and (ii) a standard image according to a matrix operation of standard-image matrix data and the color image data, the standard-image matrix data being matrix data for forming the standard image.