The purpose of this research is to analyze the factors that create a sensation of balance or unbalance when a color image is observed depending on the light transmitted, reflected, and/or emitted by the objects that appear in it. This study is carried out by calculating the center of gravity (CG) of each image. The weight and the CG are obtained by calculating the force resulting from the different visual weights that make up the visual image and its position on this. When the visual CG and the geometric center coincide, it is recognized that the image is balanced. The action that acts on the balance of the lightness of an image is labeled as the visual weight. The visual weight of a figure is defined from the amount of visible light coming from it and the space occupied by this in the visual image. The colors show us the amount of light coming from a figure, while the shape provides us with information about the space that it occupies. The study explores how the qualities of appearance of three-dimensional objects affect visual weight and how it can vary due to changes in light, motion of objects or the perspective of the image. Since these calculations can be very complex, we have developed the software called PesoVisual that automatically performs these operations on digital color images. Similarly, this software enables the analysis of the variability of the visual image. (c) 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 175-187, 2016