Davy,
From what I've learned, ordering B&W on the "color" paper can leave a yellow or green tint on the print. I've just ordered a few different items for myself to test the waters, and can post my findings when they come. Things lke:
- B&W on B&W paper, and the same image on Color paper
- My B&W conversion, then letting the lab do a B&W conversion on the same image
- and more ..
To change the option, you need a separate price list (you can duplicate your original price list, then on the new one only select B&W paper) .. then when in the admin view, double-click on a B&W image. On the right, go to "Print Ordering" and "Edit". There's an option to un-select the "same as existing gallery" option and choose a separate price list.
Hope that helps, this is the first time I was able to post an "answer" in these forums rather than a question! Phew, maybe I'm making progress! 