[filmscanners] Re: Scanner profile builder

["Tony Terlecki" <ajt@mrps.demon.co.uk>]

On Mon, Aug 12, 2002 at 05:35:39PM +0200, Alex Zabrovsky wrote:
> Has anybody have a chance to try Kodak's COLORFLOW ICC color profiles
> builder software to calibrate his scanners ? (especially would be interested
> in IV ED calibration experience).
> I found quite rave review of this thing from Bruce Fraser using it on
> LS-4000. According to him it would noticeably improve shadow rendering
> performance opening up considerably (Nikon's CMS is disabled of course).
>

Are you referrring here to Bruce's reveiew of the LS4000?

Firstly any scanner profiling software will probably produce a similar
result - basically they all function by scanning an IT8 target and build a
profile from that. I have done this with EZColor and the results are an
improvement over what I can get with the NikonScan software. Colour accuracy
is the main goal of profiling, if shadow detail is improved it *may* be a
bonus - it may also be a shortcoming.

I think shadow detail from any of these packages is far from ideal, and
can easily be improved with a simple curves adjustment after the fact if
you think the image requires it. The detail is usually there in the raw scan,
just not usually brought out sufficiently well by the profile.

Bruce mentions that the Imacon produces better shadow detail than the
LS4000. That may be so but his examples were very poor representations of
what he was trying to convey. The Imacon image has a very compressed tonal
scale which I presume was necessary to raise the lower tones sufficiently
high enough to present more shadow detail. I bet a quick curves manipuation
on the LS4000 image could produce a similar result because it is capable of
good shadow detail. Many people would manipuate shadow areas of an image
differently to prevent tonal compression in the mid & high tones (which
often results in washed out colours).

In summary I would say that profiling software is useful to get better colour
accuracy from you scanner. Shadow detail is better served by making your own
custom curves for post processing or by manipulating images on an individual
basis according to your needs.

--
Tony Terlecki
ajt@mrps.demon.co.uk
Running Debian/GNU 3.0 Linux

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