1. A computer-implemented method, comprising: receiving a digital image of an object; processing the digital image to determine pixel densities in the digital image; generating a user interface for display on a display device, the user interface including a display area; generating a three-dimensional cube representing a color space for display in the display area; and generating a plurality of spheres for display within the cube, where: the spheres are sized to represent the pixel densities in the digital image; and the three-dimensional cube and the spheres are generated for display over the digital image.