Re: filmscanners: LED Illumination for Film Scanners

[Arthur Entlich <artistic@ampsc.com>]

Obviously, how evenly illuminated a field of light sources appears to be 
has to do with at what distance (or magnification) they are being viewed 
at, and through what media the light is being shown through.

There are all sorts of methods of mixing and baffling and diffusing that 
can blend illumination.  One could say a color CRT isn't evenly 
illuminated either, as it is bunch of lines or spots of varying 
phosphors and a shadow mask through which the electron guns activate the 
phosphors.  Yet, from a few feet away a good quality and properly 
aligned, converged and degaussed color CRT can look like a very pure 
field of white (or whatever other color) light.

So, without knowing how large the LEDs are, how bright they are, how 
close together they can be placed, how even their output, how closely 
they will be viewed and ultimately what their light is "processed 
through" I have no reason to believe they cannot produce even 
illumination for a specific application.

Has anyone actually seen the illumination system used in a Nikon 
scanner?  How large are the LED "elements"?  Are all four "colors" 
integrated into one LED element (R,G,B, IR), or are they individual? 
Are they diffused via some material or light chamber?

Art

Austin Franklin wrote:

>>> What I don't yet understand is how the illuminant
>>> is evenly distributed over the film width,
>> 
>> Lots of LEDS, spaced to give even illumination.
> 
> 
> But that's the point...you CAN'T space them to give even illumination.  Just
> a single LED is unevenly illuminated in and of it self!  It's typically a
> mounded plastic piece, which is really not very consistent.