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Projecting Your Image - part 2 of 1 2 3

by Mike McNamee Published 01/02/2008

The entire exercise was fraught with difficulties.

1. The interaction between the screen and the LCD projectors produced ugly moire fringing, a problem we had never seen before either on other screens or projecting onto a painted wall with either of the projectors. Digital data projectors should be used on plain matte white screens, so if you have a fancy legacy, 'beaded screen' you may have to put it to one side.

2. The DLP projector was difficult to photograph because of the cycling between red, green and blue as the spinning filter wheel ran past the projected beam.

3. The vagaries of the Windows' operating system made it difficult to decide when and if the profile was kicking in. The Mac had the edge here with its ability to use one profile for its own laptop screen and another for the projector - on a laptop PC you can have one or the other profiled but not both - another example of the crap way that Windows deals with photographers!

Undaunted we pressed on with our tests and here is what we found. We know we have only just scratched the surface and ended up with more questions than we started out with!

The projectors were:

Epson EMP 1810 LCD Technology
Optoma EP 725 DLP Technology
Mitsubishi XL8U LCD Technology
(plus other projectors and data from our archives!)

For assessment we checked the overall grey balance (visually), the highlight differentiation, the shadow differentiation and the quality of the Granger Chart. All are subjective tests. We also measured the colour temperature by white balancing the image from the camera in Lightroom - not a very scientific method but it did give us a few pointers. As so often happens we made a bit of a break through very late in the testing (these things always happen just as you are about to go to press!). We managed to plot the actual gamut of the profile from the screen data. This seems to be a pure, objective measure which we can exploit in future testing. Time will tell how powerful a tool it will turn out to be but at first look it certainly put the projectors into the same ranking order that our test audience decided upon. The main variables will be the room illumination level, the screen type and the size of the projected image. With those constraints in mind, the measured values were as follows:

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1st Published 01/02/2008
last update 09/12/2022 14:58:16

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