I have fluorescence images from a microscope -- they are in TIF format. I simply want to merge these together, I.e. overlay them. I have images in red, green and blue channels. My typical method of doing this is simply to make a new RGB image in photoshop and paste each of the channel images into their respective channels. I do Ctrl+A to select the image of interest, then Ctrl+C and Ctrl+V it into the channel. My question is: how can I do this with brightfield image as well? The brightfield is sort of like another channel, since it does not fit in red, green or blue channels.
How can I merge/overlay these images, such that all fluorescent channels plus the brightfield (which is a greyscale image) are visible?
My images are 16bit and I'd like to merge them like that. My understanding was that ImageJ forces one to go to 8-bit but I'd prefer not to.