I tried using my Black and White contrast filters on my Canon G2 for the purposes of demonstrating the effect. I set the camera on a tripod and took a meter reading. I switched to manual and set a shutter speed to include the required filter factor. The resulting images were taken as colour JPEGs and then converted to B&W in Photoshop. The result was that the stronger the filter the worse the contrast. The red produced a very flat image. Examining the original image I found the red channel was mostly blown out. The blue channel was mostly suppressed. I presume the flat image is then the result of the Bayer interpolation - the dark blue and the light red compressing the tonal range across the whole image. The B&W mode (which I used to visualize the final image) produced the effects I expected to see but the image captured in colour and then converted bore no resemblance. I certainly don't want to reopen the can or worms about whether you can reproduce all the effects of B&W filters using the channel mixer. Does anyone use B&W filters on digital cameras ? Can someone give me a solid explanation of this effect ? What does the B&W mode on the camera do - just use the luminosity from each pixel ? As a side question I know the G2 uses the CCD to meter, does it use only the Green pixels ? Does the histogram display only the green channel ?