The audit to color saturation control tools of modern computer graphics software is carried out. Under assumption of the measuring application for saturation transform, the accompanying error is defined. In the case of a virtual instrument, this error is described as a three-dimensional value and the classification of such error components is proposed. Within the framework of a three-dimensional model, the structure of a saturating toolkit total error is systematized. Properties of one component – the hue non-uniformity of conversion – were studied for 24 graphic software packages. Its peculiarity that is critical for the certain graphic information integrity aspects in the course of saturation-contrast transform was revealed. Anticorrelation of the hue non-uniformity with the previously found brightness shift was detected. As a result, the investigated software product does not guarantee the adequacy of color saturation-contrast control in image analysis tasks. The last does not allow these packages to be used within forensic expertise anyway. Results of analysis for the software package being devoid of both errors (the hue non-uniformity and the brightness shift) are presented. So the earlier announced system requirements to maintain the initial color hue and color brightness are to be supplemented by the uniformity requirement for color saturation conversion process itself.

Keywords: Software metrology, color saturation transform, saturations’ contrast, contrast enhancement errors, graphic information integrity, expert applications