P3D Re: Anaglyph Projection

["Gregory J. Wageman" <gjw@xxxxxxxxxx>]

Dr. T. wrote:

>BTW, I was conducted by a person who has anaglyph SEM images in the
>computer and wants to project them using an overhead projector.  Trying to
>make transparencies (using a color printer, I imagine) and projecting them
>with the overhead projector did not work very well (I was not told why, I
>suspect the colors did not transfer very well and the overhead projector
>builds up contrast and spills out a lot of light)  I wonder if one of these
>units that project directly the image of the computer screen, might have
>worked better.  Has anyone tried it?

If you think getting accurate color rendition is difficult with film, you
should try it sometime with a computer system. :-)

The problem is that with the average computer setup, it is usually completely
uncalibrated.  The gamma and color temp. of the monitor may be essentially
random (depends on the monitor), as may be the gamma and color temp. of the
printing device.  Do the system's printer drivers know how to accurately
reproduce color on the particular printer in use?

One might tweak the colors to extinguish well on the screen, but if the
printer driver isn't calibrated to match the monitor, what comes out of it
may be entirely different.  Then there's what happens to the color values
when actually projected (what's the color temp. of the projection lamp?).  A
calibrated system, such as used for pre-press production work, would give a
much better starting point, but you still have the final projection step
which remains uncalibrated.

A digital projector would suffer from the same problem, but could be dialed
in interactively, far easier than a printer (which will typically require
many time-consuming, trial-and-error adjustments), and would also tend to
be more stable in the long run once calibrated (the transparencies can be
expected to fade rather quickly; ink jet colors in particular have a very
short life, even in dark storage).

It's not impossible to do, and with some effort could probably be made to
work well.  I'd be surprised to have it work well out-of-the-box, though.

	-Greg W.


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