[filmscanners] RE: Digital Darkroom Computer Builders?

["Paul D. DeRocco" <pderocco@ix.netcom.com>]

In the real world, what winds up in the video card's lookup table is a
gentle curve whose slope probably remains well between 0.5 and 2. If anyone
can see the faint posterization that comes from having a 256x8 table under
any circumstances (and I never have), adding two fractional bits would
certainly eliminate it. Of course I'm talking about adding two actual bits
of data, not just a couple of zeroes.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com

> From: Austin Franklin
>
> Em, well...you are saying, say, a 1024 bit output LUT with a 256 input?
> That entirely depends on the data in the LUT on whether it does as you
> suggest (eliminate gaps/combining).  The same curve data set in a
> 8 in 8 out
> vs an 8 in 10 out LUT will give you the exact same 8 MSBs, so Adobe would
> have to be aware of this.  I assume you are talking about the curve being
> created to provide 10 bits out?  Still, that can, depending on the curve,
> cause gaps/combining...and if you take the 8 MSBs of the 10 bits, they
> should be the same as the 8 bits out of an 8:8 LUT (which was my point
> initially), or the "base" curve would be different.  So, I don't see how
> that helps, unless the lower two bits were visibly
> perceptible...and as you
> say, it may be (probably is) visibly imperceptible.

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