Adobe RGB (1998) is the best RGB colour space to use for general
work, including scanning, digital photography and image manipulation
and adjustment. It covers a broad part of the visible spectrum, and
can be achieved by decent quality displays. The sRGB standard is more
of a lowest-common-denominator colour space, one that covers the
range of colour that you can reasonably expect to be achievable on
the average bog-standard display - NOT on a high-quality display. (As
I sometimes tell my students, the ‘s’ in sRGB is for ‘standard’, but
there’s another word beginning with ‘s’ that could equally be used.)
My Photoshop image fine-tuning is done in Adobe RGB. Then, because
browsers and browser plugins assume image content is sRGB (and hence
produce particularly dull renderings of content that’s in a broader
RGB colour space) I convert the profile to sRGB in Photoshop. (That’s
Edit > Convert to Profile - NOT Edit > Assign Profile.) This gives me
the best standard colour space for editing and then produces the best
final results in sRGB once I’m done. Of course, when working for
print I don’t convert to sRGB, ever.
Calibration is actual adjustment of the behaviour of a device,
normally a display. The idea is to get the device working as best it
can, then to profile it to measure just how well it performs.
The thing to remember about profiles is that they don’t change your
image content, they just describe the characteristics of the device
they are for…
A monitor profile describes the strengths and weaknesses of that
monitor, and the colour management system adjusts the signal sent to
that display to compensate.
A scanner profile describes the way the scanner’s results match or
don’t match the original, so the colour management system knows what
compensation should be used when dealing with something with that
scanner profile.
A printer profile describes how well or otherwise the printer manages
to do at rendering specific colours, shades and tones, so the colour
management system can take that into account when print data is
compiled and sent to the device.
You can use the profile of one output device to proof something using
a different output device. For example, you can use a (high-quality)
inkjet printer to proof the way work will look on a four-colour
offset litho press. The caveat being that you need accurate profiles
for both, and that if the proofing device can’t quite render the same
tones/hues that the destination device can then the proof will be
limited in those respects.
If you use CS3 or CS4 then select one main app to configure the
colour settings - I suggest Photoshop as it has the widest range of
controls - then save those, go to Adobe Bridge, and pick this as the
suite-wide synchronised colour settings.
I don’t use Adobe’s generic colour settings; they are safe enough,
but certainly not ideal for sheet-fed work on normal coated stock. My
standard settings for regular print work and all photo manipulation,
when I don’t have specific press profiles to work with, are as
follows:
Working Spaces
RGB: Adobe RGB (1998)
CMYK: Coated FOGRA39 (ISO 12647-2:2004)
Gray: Dot Gain 15%
Spot: Dot Gain 15%
Color Management Policies
RGB, CMYK and Gray: all Preserve Embedded Profiles
Description:
“General-purpose colour settings for print. Adobe RGB and FOGRA39”
FOGRA39 is a reasonable fall-back standard for general offset litho
work. It is a recognised European standard and a ratified ISO
standard too. I recommend this over the slightly thin results that
you can get from US Web Coasted (SWOP), the normal defaults. And
whatever you do, don’t use Euroscale - that’s based on inks that
haven’t been manufactured for years!
Remember, RGB colour can be brighter and more saturated than can be
achieved in CMYK, but there are a few parts of the CMYK spectrum
(notably pure 100% cyan) that can’t be precisely rendered in RGB.
Colour conversion from RGB to CMYK should be done only when you know
what standard to use (that’s the FOGRA39, US Web, US Sheetfed, Web
Coated SWOP, etc., or you have a specific press profile). Going from
RGB to CMYK throws away data that you can’t get back, so do your
homework first - even if this means just picking a general standard
that seems appropriate.
You can use an all-RGB workflow and have your colour converted to
CMYK as late as possible in the prepress process. This ensures that
your RGB colours are converted as appropriately as possible, but it
also means that you have taken your hands off the wheel (as it were)
before that all-important point. If you want to match precise CMYK
colour values then you need to produce those yourself. So - in these
cases, when working for print, specify colours in CMYK.
k (done ramblin’)
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