ChApter 2. digitAl workFlow
82 For more on textbooks in digitAl photogrAphy, visit http://www.photoCourse.Com
Color Management—The Workflow...8
If you don’t do anything about controlling color, it’s amazing how good your
results are with most camera, screen and printer combinations. If nothing
else, the colors are pleasing if not accurate—mainly because so many cameras
and other devices have been designed to display and print sRGB images. In
fact, other than skin tones, color accuracy is rarely important to most people.
If the yellow flower in the scene is yellow on the screen or in the print, that’s
good enough—who cares, or can even tell, that it’s not the exact same yellow
as the subject’s. However, photography is a visual art and when you start us-
ing RAW image formats and other color spaces, you soon notice things about
colors that you never noticed before, and for many people accurate colors
become more important.
As you prepare your images to be displayed and printed, you move them
through the workflow. As you do so, colors rarely remain predictable and
consistent. The image on the display differs from the original scene, and the
printout differs from both. When you then share images with friends, they
look different on their screens or printouts than they do on yours. To see this
for yourself, visit an electronics super store and look at the walls of TV sets,
all with slightly different colors. If you post your images on the Web, they will
vary just as widely when displayed on other systems.
Color management systems (CMS) are designed to help you keep the colors
in your images as consistent and predictable as possible as they pass through
the various stages of the workflow. Although you can’t control other people’s
display devices (or even many of your own, such as the TV or digital frame)
you can ensure that your image colors are as close to perfect as they can be.
To accomplish this, a color management system adjusts colors between devic-
es that have different gamuts so the colors remain consistent. For example, a
scene will have one gamut, an image of it another, the display and printer still
others. As your interest in this area grows, you’ll find that color management
systems are a great deal easier to use than they are to understand or pay for.
There are only two steps, creating profiles of your devices and using those
profiles to display or print images.getting reAdy to Color mAnAge—CreAting ProFileS
The first step in color management is to measure how much your devices
vary from a known standard. The differences are measured and stored in text
files, called profiles, with the extension .ICC or .ICM. The color management
system uses the information stored in these profiles to determine what color
adjustments are required to make the colors in an image display or print as
accurately as possible. There are various kinds of device profiles:- Image profiles have been developed for sRGB and other color spaces.
These profiles define the colors in an image in a generic fashion and are
embedded in the image at the time it’s captured. In some cases these profiles
(rather than input profiles discussed below) are used by color management
systems. - Input profiles for specific digital cameras are fraught with complications
because the camera heavily manipulates JPEG images and RAW convert-
ers do the same to RAW images. Unless you are photographing under a very
controlled studio situation it’s better to use the profile for the image’s color
space, rather than a profile for the camera.
One thing that’s
often overlooked is
a consistent viewing
area. Color experts
recommend a neutral
colored room with
diffuse fluorescent
lighting with complete
spectrum tubes and
ideally egg-crate
lighting diffusers. If you
don’t have the money
for a new room, a color
viewing booth is a less
expensive alternative.
Courtesy of Just-
Normlicht.
TiPs- Profiles have their
limits since there are
many devices such
as tVs, cell phones,
and digital picture
frames that don’t
recognize them. the
same is true of appli-
cations such as Web
browsers. - printers at most
commercial labs,
including those that
make prints for most
photo-sharing Web
sites shine light on
traditional silver-
based photographic
paper to create
prints. these work
best with srGB im-
ages. - Inkjet printers
and printing presses
create images with
ink so work best
with wider gamut
color spaces such
as adobe rGB and
prophoto.