Color mismatches

If you have a color mismatch between virtual proofs and hard copy proofs, you might need to adjust the white point of your monitor to optimize the visual match. An adjustment to the white point can be helpful when the primary issue is white and/or gray balance, for example, looks warm or looks cold but it will not be helpful when it comes to matching hard copy proofs with OBA (optical brightener additives). You should only adjust the white point of your monitor as a last resort.

Important: You can eliminate most chromaticity differences between virtual proofs and hard copy proofs by correctly setting up your viewing environment. For instructions, see the Matchprint Virtual Best Viewing Practices Guide, available from the KODAK MATCHPRINT Virtual Technology site at http://www.kodak.com/US/en/prinergy-workflow/matchprint/default.htm.

One or more of the following factors may contribute to the mismatch:

• The lamps in the viewing booth are old or have different lot numbers.

• Ultraviolet light interacts with the brighteners in the paper stock.

• The qualified monitor is old.

• The white of your paper stock has changed.

Adjusting the white point of your monitor

Requirements:

• The qualified monitor is calibrated.

• Your viewing environment is set up correctly. Ensure that:

  • The viewing booth luminance matches the monitor luminance.

  • You have controlled the ambient lighting.

  • You have the recommended viewing booth lighting.

  • You have used the Kodak Reference Proof kit to test the color matching between virtual proofs and hard-copy proofs.

1. On the Mac computer, in Finder, select Applications > Matchprint Virtual.
2. Double-click MVCalibrator to start the Matchprint Virtual software.
   

3. In the MVCalibrator window, on the right-hand side, click .
   The White Point Adjustment tool is displayed in the middle of the MVCalibrator window. If you have multiple monitors, you will need to perform the adjustment on each screen.

4. While comparing the paper whites, adjust the b* slider:
   • Move the slider down to add blue—that is, to subtract yellow.
   • Move the slider up to add yellow—that is, to subtract blue.
   Important: If you need to move the slider beyond the maximum, replace the viewing booth’s lamps or the monitor.

5. While comparing skin tones, reds, or purples, adjust the a* slider. This adjusts the neutral grays and skin tones based on the white point of the fluorescent lamps.

   • Move the slider to the left to add green—that is, to subtract red.
   • Move the slider to the right to add red—that is, to subtract green.
   Important: If you need to move the slider beyond the maximum, replace the viewing booth’s lamps or the monitor.

6. When you are satisfied with the adjustment, follow the instructions in the Matchprint Virtual Best Viewing Practices Guide and use the Kodak Reference Proof kit to test virtual and hard-copy color alignment. Pay close attention to skin tones and neutral grays.

7. If you have multiple monitors, position the MVCalibrator window on another monitor and select it by clicking its thumbnail that appears above the Luminance Mode.
   Move its sliders to the same positions that you set for the first monitor.
   Use those settings as a starting point and make additional adjustments as necessary.

8. When you are satisfied with all adjustments on all monitors, click Save.
9. Close the MVCalibrator window and select MVCalibrator > Quit Kodak MV Calibrator.

10. Recalibrate each monitor and test virtual and hard-copy color matching according to the instructions in the Matchprint Virtual Best Viewing Practices Guide.

11. If you need to restore the white point of your monitor to the factory default, start the MVCalibrator application and access the White Point Adjustment tool and set the slider values to 0.