colorimetric rendering
colorimetric rendering
- Subject: colorimetric rendering
- From: Henrik Holmegaard <email@hidden>
- Date: Fri, 6 Jul 2001 07:01:56 +0200
"JLKSHORE" <email@hidden> wrote:
What in simple terms is the difference between absolute and relative
colorimetric
rendering intents? Also Perceptual?
RGB working spaces don't have intents in the sense of blocks of
numbers that cause the profile to behave differently.
Blocks of numbers that cause the profile to behave differently are a
property of printer profiles.
A printer profile has in its table of contents entries that refer to
blocks of numbers. The entries are for Lab -> CMYK and CMYK -> Lab.
All the entries in each direction are allowed to reference the same
block of numbers, in which case all the intents behave the same, or
different blocks of numbers in which case they behave differently.
Nobody uses a different block of numbers for Relative Colorimetric
and Absolute Colorimetric. The TOC entries refer to one block of
numbers, the relative colorimetric block. When the profile is run,
and you choose to use it for an absolute colorimetric conversion, the
XYZ data in the wtpt (white point) tag is calculated into the
relative colorimetric table.
It can be discussed back and forth (and forth and back, I'm sure)
whether there is much point in having a separate behaviour for
Perceptual and Saturation. Personally, I'm fine with them behaving
the same. I don't have any use for a rendering that prefers
saturation. If I need such a rendering, then I am trying to match a
standalone color. And for that I don't want an interpretive intent at
all, but Absolute Colorimetric as in the Logo ColorPicker.