This isn't a particularly useful technique, but it's a great way to see how digital cameras put together color images. Like LCDs, digital camera sensors use colored sub-pixels to put together an image. Instead of displaying red, green, and blue, sensor sub-pixels individually react to red, green, and blue light. The end result is a pixel (or rather, millions of pixels) that can display a wide variety of color, but it's only because of the intensity of each sub-pixel handling individual RGB channels.
You can see the individual color channels in Photoshop by enabling and disabling the channels in the Channels pane. You can even enable two channels at a time and see how they combine with each other to produce the full palette you see in your photos. If you want to get more hands-on, you can also capture individual color channel photos, using your camera, a tripod, and some colored filters.
put together the process (admittedly, as a means of promoting its series of handheld camera and flash filters). Let's run through the steps.
Between the black and white format and the colored filter, you've captured three separate exposures of three separate color channels. In Photoshop, make a new image the size of your camera's photos. Open the three shots you took and keep track of which exposure was which color.