[Tig] why vectorscopes aren't that useful for color matching

glenn chan glennchan
Sat May 20 21:24:55 BST 2006


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Thanks to oktobor for supporting the TIG
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I never said that vectorscopes weren't useful.  They certainly are.  But
(IMO) for color, chroma is not intuitive... that chroma is proportional to
luma makes it hard to determine the saturation of colors by looking at a
vectorscope.

As far as white+black balance goes, my (limited) experience is that
vectorscopes work well when shooting neutral colored objects (i.e. white
paper, charts) but not so well when dealing with real world images.  To my
eyes, the trace on the vectorscope is ambiguous as to which part corresponds
to a neutral color.  I find that I get more accurate results by cranking the
chroma to make white balance more obvious (crank the chroma and look on the
monitor to see what happens to the neutral colors).  Or if available, many
software-based color correctors have an eyedropper that lets you sample a
neutral color, and the color corrector does the white balance for you.  I
find that approach the fastest (for a mouse+keyboard interface anyways), and
accurate enough.
*If you wanted to be perceptually accurate, then you wouldn't need a
vectorscope for that.  You'd of course still need something to guard against
color drift.

Because I work with software-based color correctors (mainly on the NLE
side), that spoils me.  You don't need a vectorscope for color balance when
you can eyedropper everything.  Matching colors is best done by eye.  That's
my experience anyways.
*I'm coming from the video side of things (Final Cut, Final Touch, etc.) but
I would presume the problems faced compared to telecine are very similar.

Glenn Chan
Toronto Canada
Currently pursuing software development
Did work for VASST / Absolute Training for Vegas+DVD Vol. 4
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