Hi Molly, A good friend of mine who is a professional photographer taught me how to create excellent full 24 bit black and white images from color. You probably know this trick but it's worth looking at if not. You bring your color image into photoshop and click on the image menu then mode. Now select Lab color mode. Now in click on image/adjustment/hue saturation/saturation. Pull the slider to 0 color. You now have 8 bits of gray information for each color. By selecting the layers/channels then lightness and then image/adjust/levels or curves, you can further tweak the value range. when you are done click on adjust/mode/RGB to set the image back to RGB mode. When you save the file you will notice that it is still as large a file as you started...cool huh?

Warm Regards, David