Re: Color temp of lamps in projection

[P3D Paul Talbot <ptww@xxxxxxxxx>]

DrT paraphrases:

> He is interested in this subject
> because he has noticed that certain pictures work better in a
> viewer vs. in projection and he wonders if the color temperature is
> the problem.

Thanks for the informative post, but I'm afraid that statement, being
overly general, masks the real question I am trying to solve.  I know
there are many reasons why some pictures are better in the viewer than
in the projector, and those reasons cannot always be easily explained.
My specific curiosity at the moment is a color balance difference
(viewer vs projector) observed in a particular slide, (a scene taken
with light of the evening sun).

[Discussion of light intenisty and color temperature issues deleted.]

> Stereo projection has the disadvantage that the polarizing filters
> reduce the intensity of the light.  The result of this reduced
> intensity is that some slides do not have the snap that they have
> in the viewer.  If you experiment and remove the polarizing
> filters from the projector you will have the impression that the
> the light gets "whiter" and the slides look better.

I don't think "snap" is really what I am looking for.  Sometimes
when the viewer button is depressed part way the bulb does not
light up completely, but that reduced intensity seems to increase,
not decrease, the golden/orange glow of the scene.  So the effect
seems reversed with the projector.  Why the difference?

Paul Talbot


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