Re: Unusual 3d Concept/Light for Viewer

[P3D John Bercovitz <bercov@xxxxxxxxxx>]

Eric Goldstein writes:
 
> John Bercovitz wrote:
 
>> 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.
 
Of course I'm the ideal candidate to write on this subject...
knowing as little as I do about this area of vision.  But how 
would the diffusion material help reduce flicker?  I understand 
that reduced light levels reduce the perceptibility of flicker; 
does the diffuser then reduce the bright spots so that the field 
doesn't have any high intensity areas in which flicker would be 
perceptible?  Seems like if you then raised the light input some 
more, the flicker would again become visible so probably this 
isn't what you mean.  Also, can't most people at least see the 
flicker with their peripheral vision?  That in itself is pretty 
annoying.
 
>> Secondly I'm concerned about how the lamp's spectral output 
>> matches up to the film's spectral transmission. 
 
> 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 
 
> The fluorescents 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...
 
I understand how three properly-chosen color filters (or reflectors) 
can generate any color when illuminated with continuous-spectrum light, 
and I can even see how they can generate any color when illuminated 
with a matching discontinuous spectrum, but I don't think I can see 
how a properly-chosen illumination spectrum can have light missing in 
an area passed by one of the filters.  On the other hand, high color 
temp incandescents have a continuous spectrum which should do the 
job because even though the blue end is weak, the eye is good at 
compensating as long as there is something there to work with.  
Not so?
 
John B


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