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Re: filmscanners: exposing C41 for scanning ( was gibberish

At 06:46 PM 6/30/01 +0100, you wrote:
>On Sat, 30 Jun 2001 07:26:58 -0400  rafeb (rafeb@channel1.com) wrote:
>> I'm hoping (without evidence) that you're mistaken about 
>> the swiveling LEDs.  A 645 negative is approximately 
>> 7,000 scan lines along the length of the strip (4.5 cm, 
>> at 4000 dpi) and that would mean 21,000 mechanical 
>> motions of the LED array (or 28,000 if you add the IR 
>> channel.)
>> I much prefer to believe they're switching the illuminant 
>> colors electronically.
>Rafe, please don't take what I said as gospel - I'm relying on my raddled 
>memory of a description I saw of the LS1000 mechanism many years ago, and 
>may well have it *completely* wrong.
>What I *think* I recall is that the LED array is both switched 
>electronically and moved mechanically at each scan line position, so the 
>successive R, G & B exposures are made with R, G & B LED's and monochrome 
>strip sensor 'looking at' precisely the same strip of film image 1 pixel 
>high. IOW the LED array is positioned differently for each channel 
>exposure, the relevant LED's turned on for the exposure duration, and then 
>the cycle repeated for the next scan line, and so on.

<snip of ASCII art -- well done, BTW>

Ah, Tony, but I do take your word as gospel... <g>
Your word is surely as good as anyone else's around here.

I guess I was thinking that the LEDs are small enough 
(and hopefully diffused somewhow) so that mechanical 
re-positioning is not required.

I am sorely tempted, but I dare not open up my scanner 
to investigate further.

I will admit that the noises emanating from this scanner 
suggest mechanical goings-on that I'd rather not speculate 
on.  IOW, a coarse clicking/rattling/grating noise that 
seems much too coarse to correspond to steps at 4000 dpi.
I've never heard another scanner (either film or 
flatbed) make noises like that.

rafe b.


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