How do I copy a channel to a layer and show it 'colorized' in its color of Red, Green or Blue?

I saw an interesting rendition of a photo on television and wanted to try to duplicate what I saw... It was essentially a color image but then the subject was placed 'additionally' in various locations in all trasparent except for the subject in a color on each layer Red then Green and then blue. When I copy a channel to the clipboard and paste it to a layer is is grayscale, so I guess my question is, how do I make that grayscale layer a color of my choosing. I've tried to alter it using image controls like hue and saturation but it stays grayscale. This is a unique concept and beyond what I've ever tried to do before so I leave it to whomever understands a bit of what I am after - in order to put what looks like 'out of register' red and green and blue images of the subject added over the top of the original base of the full color photo.