At left: Orientation-Independent-DIC image of a live mouse cell visualizing density of materials. The bright regions with the heart- and sphere-shapes are compartments in the cell called nucleoli. At right: A conventional fluorescence microscopy image of the same cell depicting only DNA. The bright regions are the heterochromatin. Some heterochromatin are marked with arrow heads for comparison between the two images. Note that they look different because the fluorescence image (right) does not necessarily show density of the materials.