Correct lighting at the press console or QC department or customer sign-off station is still the cheapest fix in color management.

Illuminant metameric failure is unavoidable when we compare our digital proofers inks to those used to print on our lithographic or Flexo presses for example.

ISO-3664:2009 defines the viewing conditions for critical color evaluation in the Graphic arts market and specifies D50 as the illuminant condition.

All calibration and profiles (exceptions exist) are based on D50 and metameric matches between proof and press will exist at D50. Under non standardized lighting conditions we will often see a significant mismatch yet numerically or by measurement there is a match.

Since few people today use measurement as their source of color evaluation and their eyes are still the initial evaluation tool of choice, fixing the viewing condition under which we do this subjective evaluation will bring you much closer to the results achieved through objective evaluation by measurement.

 I have personally witnessed more times than I care to remember how much waste has been generated and hours of time lost due to incorrect lighting. All this can easily and relatively inexpensively be fixed with the correct lighting.