Fluorescence emission intensity from a culture of Indian Muntjac deerskin fibroblast cells stained with the nucleic acid stain TO-PRO-3, which targets the cellular nuclei. The visible light absorption maximum of TO-PRO-3 is 642 nanometers and the emission maximum occurs at 661 nanometers. The image was captured in 12-bit grayscale mode, but subsequently pseudocolored by converting to the RGB color palette and setting the green and blue channels to zero (to produce a red image). Note the bright fluorescence intensity exhibited by the individual nuclei in this preparation.