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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, October 26, 2000 4:42 PM
> To: [EMAIL PROTECTED]
> Subject: Re: VueScan & Epson 1200S success & question.
>
>
> In a message dated 10/26/2000 7:19:20 AM EST,
> [EMAIL PROTECTED] 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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