Tints under 12% don’t show up, using Imac Screen.

Issue: When using any tint of any colour under 12% in QuarkXPress, Photoshop the Imac screen does not show this. It shows it as plain white.
Im a Graphic Designer and this is a very important issue, many tints I use are 7% these come up very dark when printed by Commercial Digital Printers. There is no problem with my ProNitron 21/650 Screen.

Which iMac is this and is it a 20" or a 24"? White or Aluminum?

Imac Details...

Imac Details... 24" Aluminum

Hardware Overview:

Model Name: iMac
Model Identifier: iMac9,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.66 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 6 MB
Memory: 4 GB
Bus Speed: 1.07 GHz

you can try experimenting with color profiles ... system preferences/displays and the color tab ( i think )

I work in tech support for a publisher and one of our designers has a very similar problem on a 24in Aluminium iMac, iMac 7.1. In InDesign he cannot see any tint below 20%, they just look white.

We've tried everything, checked the colour profiles, reinstalled the software, run diagnostics, checked all the firmware and graphics card are up to date. No joy. If anyone has had this problem and has a solution we'd also be very grateful to hear from you.

GeoffStrange can I ask you: Did this problem come on all of a sudden or has it always been an issue?