Michel Corbin wrote:
I can't seem to figure out how to display the Color Model EXIF tag, but when I filter on it I only get images if I enter RGB (ie if I select Color Model Stars with G nothing shows up).
Right you can filter on all the EXIF data even if a particular field is not being displayed.
Most likely your camera is doing what my 40d is doing and reporting the actual color space and mode used for the image.
My Canon has a setting Picture Style which is set to Monochrome when shooting B&W

but unfortunately Aperture dose not include this EXIF field when it reads the data for this camera.
Most digital cameras as well as programs like Aperture create B&W by desaturating the image (basically). The color space is still sRGB (or what ever color space you are using). As a matter of fact Aperture is only designed to work with sRGB images, true gray scale images do not work well in Aperture.
So the actual color model and mode when shooting B&W is still color.
BTW what camera are you shooting with? Also keep in mind that all of this just applies to JPG images. Raw images are always full color regardless of what the camera settings are.
regards