If you want to match to the prints, you have a couple options:
1) Calibrate your monitor and then get a print profile from the company who makes your prints. Then you need to use their print profile when creating the output that you send to them (as a JPEG or a TIFF). This should work.
2) You can get a calibrator which actually calibrates your display as well as the output. The display pro won't do that. Probably more like the photo pro: http://xritephoto.com/ph_product_overview.aspx?ID=1913
(there may be a product on X-rite that's less overkill but their site is a mess)
Is there a way I can use the calibrator to match the results I get from a print supplier? Or is it just a case of trial and error?
You should get a printer/paper profile from your printer for each printer/paper combination you use. Install them, and do your final edits with soft-proofing on, with the appropriate profile selected. (The reason to profile is to eliminate trail and error.)
Also, I sell my pictures via a website and I've often wondered what is the ideal brightness level to use on my monitor when preparing pictures to match how they'll be displayed to people viewing them on their home computers, most of them aren't photographers and won't have calibrated monitors. If they're likely to have their monitors set to full brightness and I adjust my pictures with the monitor set to only half brightness (as the X-Rite calibrator suggests) then they could look over exposed on the customer's monitors.
I recommend six things :
- Double-check your use of the calibrator. Nothing you've said indicates there are any problems, but _everything_ hinges on proper calibration (and un-hinges on incorrect calibration).
- Use a monitor brightness of 80-95 for _editing_ your pictures. I use 85 (or as close as the monitor can get). Make sure your viewing environment is good (no sunbeams in the room, not a lot of ambient light, no glare on your monitor, no brightly colored objects near your monitor, etc.) The edited picture is your base-line for publication.
- Add adjustments on publication based on the file's intended use. Your output sharpening, brightness, contrast, etc., will be different for each exact use/publication, and (ideally) should be tailored to that. Soft-proof with profiles for all printing.
- Use a run-of-the-mill monitor profile and soft-proof pictures that will be seen by clients on their own run-of-the-mill monitors prior to publishing them. This, clearly, is somewhat kin to net-fishing at night; your goal is somehow to anticipate the _average_ crappiness of the viewing environment, and balance the correction to the degree to which your pictures are compromised by the display against the number of clients you are able to usefully include.
- Educate your clients. Add to your clients' viewing pages one of those 10-levels-of-grays bars, and some text explaining that if they can't distinguish all ten levels on the monitor they are using, they are likely missing out on much of the photographic excellence you have put into the pictures, and a link to a site explaining how to use the built-in OS tools to adjust their monitors.
- All that said (and speaking mostly to myself), don't let exactitude over-ride sensibility: you are bringing a _far more_ attuned attention to the product you provide than any but 1 in 50 of your clients will or can (might be closer to 1 in 500).