Moreno wrote:
>And taking things one step further, a dense LED array positioned closer to
>the negative could even be
programmed to provide some degree of selective dodging/burning/variable
constrast control. With an appropriate control mechanism, a user could
adjust for dead even lighting across the easel for a specific lens/format
size combination.
This is a very signifficant "AhHa!" IME. I'm actually surprised that no
programs, to date, are using that possibility. As I might have said sometime
ago, we users *do* have some ideas worth considering, from time to time.
;-)
Best regards--LRA
>From: "Moreno Polloni" <mp@dccnet.com>
>Reply-To: filmscanners@halftone.co.uk
>To: <filmscanners@halftone.co.uk>
>Subject: Re: filmscanners: LED Illumination for Film Scanners
>Date: Wed, 20 Jun 2001 15:05:09 -0700
>
> > > A couple of years ago someone on the darkroom newsgroup was working on
>an
> > > LED light source for enlarger heads, utilizing clusters of
>high-intensity
> > > LED's. I don't know what happened to the project, but at the time a
>lot
>of
> > > people were really excited about the technology and the initial
>results
> > > showed a lot of promise.
> > >
> > >
> >
> > Yes, and look at how uneven the lighting is.
>
>Quoting a recent post on this list: "And you can tell this from a 72dpi
>JPEG
>image?"
>
> > For an enlarger, that may turn
> > out to be a very bad idea, simply because you can't adjust each
>individual
> > LED for even illumination. At least with a CCD, you can adjust the gain
>for
> > each sensor element to get even illumination.
>
>Why can't you adjust each LED for illumination levels? For instance, the
>designer could quite easily vary the voltage levels throughout the array to
>compensate for enlarger lens light fall-off. And taking things one step
>further, a dense LED array positioned closer to the negative could even be
>programmed to provide some degree of selective dodging/burning/variable
>constrast control. With an appropriate control mechanism, a user could
>adjust for dead even lighting across the easel for a specific lens/format
>size combination.
>
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