Antifadent Solutions reduce the photo-bleaching, or fading of the fluorescence of dyes used for labeling biological species. The fading of fluorochrome dyes is a particular problem in fluorescence microscopy, such as in immunofluorescence studies. Fluorescent dyes are also used as cell markers, for following the uptake and release of calcium from cells for example, and for characterizing cell surfaces. For work at high magnification, a non-fluorescent immersion oil is available.