Digital Projection Equipment Calibration

We've now completed three competitions since calibrating our computers for the projector and I believe that we have a stable, repeatable and quality projection capability. At the December Workshop we took some time to test a newly calibrated replacement laptop computer. We were able to connect both the old and new laptop to the projector simultaneously and switch between the two, projecting the same images with both. We used calibration targets and some of the November competition images as test subjects. The differences between the old laptop and new laptop were minimal, with all of us having difficulty identifying which computer was in use at any given time. This new laptop was slated to be used for the competition in December but differences in the way that integers are calculated between Visual Basic for Applications (VBA) in Office XP and Office 2007 meant that the competition software was miscalculating the number of awards. Many thanks to Scott Musson for providing a modern and highly capable laptop for the club's use. The competition software should be updated to address the calculation bug in time for January's competition.

The projector's color gamut is slightly smaller than the standard sRGB color gamut as seen in the comparison in Illustration 1. The grey outline is the sRGB color space, the colored areas are the colors that the projector is capable of producing.

Illustration 1: NVPS Projector as compared to sRGB IEC61966-2.1

Because of this difference in color gamut, heavily saturated colors will tend to project slightly flatter on the screen, and blacks will tend to muddy down to a single color. Using the image in Illustration 2 as an example, the blacks in the Kodak CYM chart (vertical greyscale strip on the right of the image) from 15 - 20 all appear to be identical.

Illustration 2: Color and Black and White Test Target

What this means is that an image that has good detail in the shadow areas, probably will not when projected. However, an image with good detail in the highlight areas probably will have good detail when projected. When properly configured, the projector produces excellent contrast in the highlights, although it appears to have a very slight green cast in the whites that has not been corrected through calibration.

We have generated an ICC profile for the projector that can be used for "soft proofing" images that are being entered in competition. We hope to make the profile available on the website in the near future, but for the time being, please email me and I will provide the profile as an email attachment, along with details on where to copy the profile in order to be able to use it from Photoshop CS2/3.

Now that the equipment is calibrated and the configuration for the projector is documented, we will continue to calibrate approximately monthly. If there are significant changes to the profile that has been provided we will update the profile and make an announcement in FotoFax.

As always, if anyone has any questions, comments or concerns about color calibration or the configuration of the NVPS digital projection equipment, please feel free to contact me.

Matthew G. Schmidt

703.975.6342

mgs@loreleistudios.com