Re: VueScan & Epson 1200S success & question.

["Bob Armstrong" <bob@armstrong.plus.com>]

<x-charset iso-8859-1>So, this is what your earlier post said you were about to send, is it?  Can
the 12 to 8 bit mapping also be done in the lightest bit so that the
'capured most dark' and 'captured most light' scan could then be merged?

Regards

Bob Armstrong

PS  Where did you get the impresion that the Epson 1200 Scanner output 12
bits per channel?  The details I read said 12 bits internal, 8 bits
external.

On Thursday, October 26, 2000, Richard Wolfson wrote:


> This just in from Ed Hamrick. I learn something every day, and often
> more than once. It's really kind of Ed to take the time to explain all
> this. Thanks Ed.
>
> Richard Wolfson
> rwolfson at LyricDesign.com
>
>
> > -----Original Message-----
> > From: EdHamrick@aol.com [mailto:EdHamrick@aol.com]
> > Sent: Thursday, October 26, 2000 4:42 PM
> > To: rwolfson@lyricdesign.com
> > Subject: Re: VueScan & Epson 1200S success & question.
> >
> >
> > In a message dated 10/26/2000 7:19:20 AM EST,
> > rwolfson@LyricDesign.com writes:
> >
> > > And a suggestion to Ed: the option of saving 48 bit tiffs should be
> > >  DISABLED when VueScan can't get more than 8 bits from the scanner.
> > >  Otherwise the software serves as an "unidicted co-conspirator," to
> > >  borrow an old Watergate term. (Maybe Nixon is alive and
> > consulting to
> > >  Epson?)
> >
> > It's actually quite useful to save in 48-bit mode.  The original
> > data from the scanner is 8-bit data, but then it gets mapped
> > back to 12-bit resolution and all film processing is done in
> > 16-bit precision.
> >
> > In addition, the 12-bit to 8-bit mapping sent to the scanner
> > uses a linear segment in the darkest part, so more detail
> > is pulled from the dark parts of slides (or bright parts of
> > negatives) than you'd otherwise expect.
> >
> > Lastly, negative film processing is very non-linear, so
> > mapping the 8-bit data to 16-bit data is useful.
> >
> > In summary, it's useful to save the final processed image
> > in 48-bit format even though the scanner only transfers
> > 8-bit data.
> >
> > Regards,
> > Ed Hamrick

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