This exercise has been very helpful in a number of ways. It has forced me to figure out how I can set the white balance on my camera, I have discovered new options in Aperture and most of all, I am more aware of how to change the feel of black and white photography, or how to emphasize certain elements.
This is the photo that I used, with clear red, blue, green and yellow elements.
Things to remember from this exercise: The filter you put on will lighten the colour of you're filtering, in this example especially visible with the colour blue. It turns around the brightness of the Holt Coldrex packages and lightens the darkest object in the picture. Without having to change the exposure in the images, it is possible to highlight or downlight specific elements of the photograph.