Re: Unusual 3d Concept/Light for Viewer

[P3D Eric Goldstein <egoldste@xxxxxxxxxx>]

P3D John Bercovitz wrote:
 
> John Vala writes about using fluorescent lamps.
> I'm concerned about two things.  The first is flickering which can
> be taken care of with high frequency electronic ballasts if they're
> available for the lamps in question.

Right. Also, the diffusion material tends to mitigate the flicker. And 
many, many (most?) people just don't "see" the flicker, even with 
standard ballasts.


> Secondly I'm concerned about
> how the lamp's spectral output matches up to the film's spectral
> transmission. Back when we had film at work (now it's all digital),
> the workers used light tables which were lit by 5000K fluorescent
> lamps but I think there's more to it than color temp because these
> had better rendition than others of the same temp.

Color temperature and CRI are only part of the story; as you say, 
spectral output is also a factor. That is, how much energy at what 
frequency across the visible spectrum. It is easy to see how an 
illumination source with a highly irregular spectral output could still 
average a color temperature of 5000 K. In fact, some types of interior 
commercial light sources have such "spikey" spectral outputs that they 
can't be corrected for daylight in any meaningful way (such as the 
general illumination we work with at my office, blech!).

The flouescents used in modern, high grade photographic applications 
(available in a variety of sizes) can be engineered well enough to be a 
good source of daylight illumination for picture taking as well as 
picture viewing. And as you'll have the same problem matching any light 
source to the film's spectral transmission, I'm not sure how useful it 
is to go too far down this road... I doubt that halogens or 
incandescents which were designed for general, non-critical illumination 
will get you any closer...


Eric G.
egoldste@xxxxxx


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