Originally Posted by Steve Ruddy
I have a Canon Pro-1000 and am printing a greyscale image on Canson Aquarelle Rag. My test prints have nice black level but when I print a full size 17x22 sheet the black level drops to to a crappy light gray...............
You must be changing something other than paper sizes to cause a difference in the print. No clue if it is a different paper, printer driver, profile, or what. But you only need to determine what you are changing and stop doing it if you want your final print to mirror your test print.
BTW, with a complete color managed system, you will learn there is no need to do test prints as your first print will also be your final print as it will look just like your screen.