Re: Colormatch vs Adobe 98
Re: Colormatch vs Adobe 98
- Subject: Re: Colormatch vs Adobe 98
- From: DScharf <email@hidden>
- Date: Wed, 30 Jan 2002 05:21:17 -0800
- Organization: David Scharf Photography
Don,
I noticed that the DonRGB was said to be created especially for working
with D50 and 2.2 gamma working conditions. What are the ramifications of
#1. working on a Mac with a 1.8 gamma? #2. working at a different
color temperature such as D65 or 6500K? Or are the monitor settings
irrelevant?
David Scharf
--
DAVID SCHARF PHOTOGRAPHY
Scanning Electron Microscopy
Los Angeles, CA 90039
http://www.microscopy-today.com/Scharf.html
_________________________________________________________
Although they are well known and often recommended, neither ColorMatch
nor
Adobe 98 can be considered 'good' RGB spaces
as they both clip saturated
colors (especially reds, cyans and magentas)
which could have been printed
on a good offset press. Adobe 98 improves
greens but makes little
improvement in reds or blues and still clips
saturated reds, magentas,
cyans, yellows and oranges very noticeably.
This clipping only shows up on extremely
saturated images and less critical
users often don't notice it. But once a
photographer sees the clipping on
their own work, they never want to risk it
again.
For six years many big photographers,
publishers, separators & agencies have
eliminated clipping with the 'DonRGB' color
space, which you can download
free from www.hutchcolor.com/profiles.html.
DonRGB is a carefully-tuned, well-proven
'wide' gamut space that encompasses
not only the full SWOP space, but also
virtually the whole Ektachrome gamut.
You can also download a sister space called
'BestRGB' which improves reds
and magentas even more to encompass the
extended gamut of Fujichrome Velvia.
In practice either one is excellent.
The big advantage of DonRGB and BestRGB over
ColorMatch and Adobe is that
your original images will lose no saturation
due to CLIPPING when you
convert into Photoshop's 'Working RGB' space.
This means you can output your
edited and archived RGB images onto a variety
of devices or presses and
always get the best color each device can
produce. There will still be some
GAMUT COMPRESSION when you go from Working
RGB to a printer's CMYK, but this
will be handled smoothly by the printer's
profile - at least if it is a good
profile. And you can preview the effects of
that compression with the
Command-Y function while editing your RGB
images.
The disadvantage of working in Adobe or
ColorMatch is that your first
conversion from scanner or camera RGB into
the working RGB space will CLIP
some colors brutally, as there is no smooth
gamut compression when
converting to a Photoshop RGB space. This
means that subtle differences
between two saturated reds, for example, will
be lost forever.
A good analogy of CLIPPING and COMPRESSION is
the difference between cutting
off your hand to shorten your reach, or
simply bending your arm. The latter
hurts less and you still have the whole arm.
You can test the clipping of different RGB
spaces by assigning them to my
'RGBXPLORER' image
(www.hutchcolor.com/Images_and_targets.html) and
converting to any good CMYK profile. Adobe
and ColorMatch usually fall well
short of 100% in saturated patches, most
noticeably reds, because the RGB
space is smaller than the gamut of a good
CMYK press. DonRGB and BestRGB
should convert to virtually 100% of C, M and
Y in their respective patches,
depending on the CMYK profile.
The only real downside with a wide space like
DonRGB or BestRGB is that you
have to be careful when sending them out into
the world. Always make sure
the recipient knows what an ICC profile is
and how to use it. If you assign
a wide-gamut profile to a normal RGB image it
will look over-saturated. If
you assign a normal RGB profile to a
wide-gamut image it will look
de-saturated.