What Color Space Do I Use? (Part 1)
[PART1 of a 2 part answer about using Color Space]
Question:
I've been trying to come to terms with color management
and working color space. What color space do you use,
and which is best?

Answer:
Short Answer: I use sRGB. There is not really a 'best'
color space, though I find sRGB best and most consistent
for what I do.

Color spaces are confusing to most people, and become a
heady topic for debate. It is good to know at least the
basics before making a choice between which to use. I
have my preferences after 15 years of working with digital
color, and they have changed with the technology...but
let's look at some concepts. In part two of this entry,
I'll add in a discussion of why I choose the color
management settings that I do.

The "Best" Way...
Working color spaces have trade-offs and advantages, or
there wouldn't be choices. If there were a 'best way' to
handle color it would likely be handled automatically
(e.g., Adobe would put best practices in place
programmatically). I consider sRGB as a "realist" color
space. It is based on standard monitor display--you deal
with colors that can be safely seen on screen (16 million
of them in 8-bit). AdobeRGB portends to make color that
is better apt for printing--it extends beyond the model
of colors you can safely see on your monitor to map colors
available in print that are not 'seen' on a monitor (also
16-million in 8-bit). The fallback of sRGB is that it
doesn't have a representation of a broader color set.
AdobeRGB is said to have a 'broader' color model, but most
people don't know what that means: to me it means the set
number of colors is mapped differently--not that there are
more or even necessarily 'better' colors. People do a LOT
of arguing about the potential advantages of using either
sRGB or AdobeRGB as a working color space.

In a perfectly theoretical arena, you'd want to work with
images in optimal conditions: colors that you would be able
to see on screen would readily translate into print.
There-in lies the rub. RGB and CMYK reproduce different
color sets. RGB is color theory based on light where red,
green and blue make up all the potential colors on your
monitor; CMYK is color theory based on ABSORPTION of light,
as inks of cyan, magenta, yellow and black that represent
all colors in print. While slightly over-simplifying here,
RGB favors reds, greens and blues to the slight failing in
representation of cyan, magenta and yellow. CMYK favors cyan,
magenta and yellow with a failure in being able to represent
the brightest reds, greens and blues. Though CMYK has an
additional 'color' (black), it does not add representation
to the theoretical space: black is added to compensate for
the inability of ink to be perfectly efficient in
absorption...black helps compensate the CMY model so that
it will have a full dynamic range. Such things as the
physical properties of the ink, paper, and available light
will contribute to the lack of perfect performance in ink absorption. All this
really means is: the colors represented
by CMYK and RGB are different, and what you see on your
monitor is not the same as what printing in CMYK can represent.

Making Compensation
There are all sorts of ways that technology tries to
compensate for the difference, such as providing
printers with additional colors, or allowing translation
using color mappings and embedded profiles. Adobe claims
that AdobeRGB is a better model in representing the
potential of CMYK, because it maps to more CMYK colors
than sRGB. It is generally argued that AdobeRGB is more
geared to printing images because of its mapping to print
colors and that sRGB is better on screen based on its
mapping for colors associated with monitor display. The
idea is intreguing, in that the color sets promise to
allow you to do more direct correction of assoviated
colors optimized for a particular use. Yet the reality
is, just like RGB and CMYK have different colors, you
can't see AdobeRGB color with reliability on an RGB screen
...it becomes a conundrum. One solution used to lie in
converting to CMYK and that works for those doing certain
types of printing, but is really not as helpful for most
people who just send images to a service, or run them out
on a home inkjet.

There are practice of using color profiles (and embedding
them in your images) helps describe the color in an image
to different devices, acting like a type of translator.
If you work in a color space and place a profile in your
image, the THEORY is that you will be able to send that
file to other devices (printers, monitors) that will
recognize the color mapping and interpret it correctly.
Once the device can interpret the color, in theory it
shouldn't matter what color space it is in: If the colors
can be translated and interpreted, the results should
have a reasonable chance of matching.

The problem becomes defining what is supposed to be matched.
If you are in sRGB, and you match what it looks like on
screen, that may make sense, but using Adobe RGB if you
match what is on screen you aren't taking advantage of the
broader color space; if you match what is not on screen,
you can't ever see what you are adjusting. But the problems
just start there whether you use sRGB or AdobeRGB. Add to
the problem the fact that not everything prints as CMYK. If
AdobeRGB gives you better CMYK and you print to a light
process or display images on the web, it may not really
offer an advantage. Another issue is the reality that color
management theory doesn't always work in the real world:
profiles can get dropped (intentionally or not) or remain
unused by devices. When you consider the world might not be
perfect, you have a better picture of the real mess and why
color management becomes such an issue for debate. One
person swears by how they achieved success in their workflow
and another opposes as they achieved success a completely
different way. The fact is that they may both be right,
either for the right or wrong reasons.

And the Answer Is?
So the answer to the question of whether you should use one
working space or another is: either sRGB or AdobeRGB can
work...but you need to accept the advantages and disadvantages
of either workflow. Which will work better for you may be
answered by taking a look at your workflow as an entire
process. That is, based on how you work with images, your
choices for what is best in adopting a workflow should be
based on what you do with images, rather than what someone
else does--whether or not they do it with success. In Part
2 of this entry (later in May) we'll look at the workflow I
use and why I've made the choices I have to give you a peek
into a considered workflow.

POSTSCRIPT
I've just finished writing my new book The Adobe Photoshop
Layers Book http://aps8.com/taplb.html . It will be out in
July of 2007. My summer courses at betterphoto.com will be
starting in June: From Monitor to Print
http://www.betterphoto.com/photocourses/RIC01.asp ,
Leveraging Layers http://www.betterphoto.com/photocourses/RIC02.asp ,
and Photoshop 101 http://www.betterphoto.com/photocourses/RIC03.asp