FluorescentCells.tif This image is made from a Molecular Probes demo slide: Cells: bovine pulmonary arthery endothelial cells Blue: nucleus stained with DAPI Green: Tubulin stained with Bodipy FL goat anti-mouse IgG Red: F-Actin stained with Texas Red X-Phalloidin ImageJ opens it as a 3 channel, 8-bit composite image. Use the slider under the image to switch channels. The subtitle has information about the current channel. For example, "2/3 (Green)" indicates that the current channel is the 2nd of 3 and its label is "Green". Open the "Channels" tool by pressing shift-z (Image>HyperStacks>Channels) and you will be able to enable/disable channels or view individual channels. Use the "B&C" tool (Image>Adjust>Brightness/Contrast) to adjust the brightness and contrast of the current channel. Change the color of the current channel by selecting a different LUT from the Image>Lookup Tables menu. Convert to RGB using the Image>Color>Stack to RGB command.