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[filmscanners] Re: Scanner calibration

Arthur writes:

> Are you sure altering color balance isn't
> "cheating"? ;-)

That depends on the direction of the alteration.  If you alter colors to
match real life, it's not cheating at all; if you alter them to create some
sort of departure from real life, it is "cheating" (with respect to
representing the image as an image from real life).

I correct colors to make sure the image looks like real life.  The typical
example is correcting light from streetlights on Provia so that they have
the proper pinkish-orange color that HPS lamps appear to have in real life,
instead of the yellowish-green rendered by Provia.

> The film is probably recording a more accurate
> color temperature than our eye does.

True for blackbody light sources, not true for discontinuous sources such as
discharge lamps, which don't have a real color temperature to begin with.
Film will often react much differently to discontinuous sources than will
our eyes, so the film rendering has to be corrected.

Additionally, even if film records blackbodies correctly, to make things
look real we must simulate the "automatic white balance" of the human eye to
some extent.  It's true that real-world images in shadow are very blue
indeed, but we don't notice that much in real life; and if the objective of
the photo is to create the same perception that we had in real life, some
adjustments are necessary.

> As you know, we color adjust chemically and
> reduce the blue component we see in shadows.

No chemical adjustment is required.  The brain handles white balance
adjustments.  Direct fatigue of retinal cells is much less of a factor, and
much shorter in duration.

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