Re: Optical printer LED light source

In article <dev4pp$sp9$1@xxxxxxxxxxxxxxxx>,
Scott Dorsey <kludge@xxxxxxxxx> wrote:
>Early Film <EarlyFilm@xxxxxxxxxx> wrote:
>>Scott Dorsey wrote:
>>
>>> Call 1-800-DIGI-KEY and ask for a catalogue.
>>
>>Sheesh! Why not just download it at:
>>
>>http://www.digikey.com
>
>Because you can't just leaf through it and look at the products compared
>together in columns. I find the web site really irritating unless you
>absolutely know what you're looking for. Also, you cannot read it on
>the toilet.
>
>>My prediction is that the LED light source will create color contrast,
>>color saturation and difficult color correction problems when used as a
>>light source for a film camera. I learned a long time ago that when
>>copying a color print to produce color negative, the best results, short
>>of doing color separations, could be had by using tungsten light and
>>camera negative film. (Hey, I'd like to be proven wrong on this as it
>>was a pain in the arse to make a D/N from a print that looked like an
>>original ECN)
>
>Why do you think this will be the case? I would not be surprised if there
>were color correction issues that turned out to be impossible to deal
>with, but I'd be surprised about color saturation issues.
>--scott
>
>
>--
>"C'est un Nagra. C'est suisse, et tres, tres precis."

Another possibility you might want to consider is using three LEDs
instead of one. This might make color correction even worse; it
probably would make it a little easier, as you could balance the
RGB channels of the light independantly. This is one area where
LEDs - forgive me - shine: if you ramp them down, their color
doesn't really change.

Put three LumiLED Luxeon Stars in there, one red, one green, and
one blue (pick your blue, though - they have a couple of varieties
that may work better than others,) and then get a couple of adjustable
power supplies. Mark 'em as RGB, and have at it.

Leo Kerr
(Note, I'm not a film-maker, but I pretended to be one in school
fifteen years ago.)


.

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