I edit and soft proof an image in Lightroom using the target Canon Pro Luster ICC profile.
Did you turn on also "Simulate ink and paper"? Try also to print from Canon own plug-in for Lightroom - just to check where the issue can be. That plug-in offers also the option to print several "proofs" on the same sheet with different settings, from which you can understand which ones works better.
Yes, I am using the Simulate Ink and Paper option.
I tried a little experiment last night, creating 3 different profiles, all using D50 white point and 2.2 gamma, but with 80, 90 and 120 cd/m2 brightness levels. Interestingly, as I changed the active monitor profile between the 3, there was absolutely zero perceived difference in the actual brightness of the monitor. So I'm wondering if the Spyder 3/ColorEyes software combination is actually capable of making an adjustment to the iMac display brightness level or is only shifting color and contrast.
I know it is definitely handling color and contrast because the difference between profiles using D65 vs D50 white point is most noticeable with the D65 being more blue and D50 more yellow. I also can readily see the difference inc contrast between the iMac out of box factory profile and my custom profile.
However at this point I'm not convinced that brightness level is actually being driven by the profile. The on-screen brightness slider in the Mac System Preferences/Displays dialog is always in the center of the adjustment range, regardless of what profile I select. I found that if, no matter what profile I've selected, if I grab the adjustment slider and move it about 1/3 of the way toward the darker end of the slider range, then reedit my image brightness and exposure based on that monitor brightness, then my resulting print is much, much closer to the onscreen view.
The problem is of course that such an approach is in-precise and not necessarily repeatable. Right now I'm visually aligning the slider with a character of text above the slider but as the monitor ages, a different position may be needed.
Would be interested to hear from other iMac users as to whether you have similar problems with your profiling package actually controlling the monitor brightness or whether you have to guess at making a manual adjustment.
I've also tried out the Canon Pro Studio and the tiled test prints. Used them to pretty good result on a couple of portrait prints. Based on the tiled print previews I adjusted the brightness up +10 in the Pro Studio settings. That works and I guess for a really critical print - like what might be put in to an exhibit or competition - that would be something to use. But I'd much rather be able to nail the print via the Lightroom Soft Print process rather than have to generate test prints.
I also like some of the Lightroom Print module features that don't exist in Pro Studio, such as the ability to create custom packages or multi-page print jobs, water marking, name plate, file information, et al.