Samples for fluorescence and confocal microscopy are prepared similarly to those for light microscopy, but they use fluorochromes instead of standard dyes. These fluorochromes are often diluted in liquid before being applied to the slide. The dyes can be attached to antibodies to target specific proteins on specific cells (immunofluorescence), or they can attach to DNA molecules to stain cells based on specific DNA sequences (fluorescence in situ hybridization, or FISH).