@Holly (OP), If you are solid on your shooting, I would stick with that. If you are scanning on a flatbed scanner, I would suggest a grey scale to be scanned w/ it in the same pass.
Like one of these: http://www.adorama.com/KKQ13.html, http://www.bhphotovideo.com/bnh/cont...dak+Grey+Scale
The patch marked w/ the "M" is .70 density and is the closest (if not right on) 18% grey. Make your adjustments to your scan and then crop out the scale for output. Or the Gretag marco.taje suggested if you care to spend the extra. They are quality.
It's never going to be perfect, it's digital. Your scanner has a color profile, so does your monitor, so does the printer you plan to use and each web site has it's own way of rendering images. It's close to impossible to get everything to match. Here is an example of a scanned negative. Open the image that is an attachment (it should open in a new window) then look at the two photos side by side. The attachment is a direct upload to APUG. The "inserted" image is the exact same file uploaded to Photobucket and then linked to this thread. Not only are the tones different, the direct uploaded one is sharper than the linked one.
Just my 2 cents, good luck,