Color Management for Black and White - Black and White in Photoshop CS4 and Photoshop Lightroom - page 4

color than the boxes of 8, 16 and 32. Burnt sienna, carnation pink and ocean
teal provided a much greater gamut for the Crayola artist to work with. It
is important to note however that no device can reproduce the full range
of colors viewable to human eyes, and no two devices have the same color
space/color gamut (or set of crayons to color with).
• The visual spectrum includes 16.7 million colors.
• The human eye can physically see only 12 million colors of those
16.7 million colors.
• The average 4-color press can reproduce only about 70,000 colors.
As an image moves from one device to another, image colors may change
because each device interprets color dif erently. When a color cannot be
produced on a device, it is considered to be outside the color gamut of that
particular device, or, in other words, simply out of gamut . You can view out-of-
gamut colors by turning this option on in Photoshop, or when softprooi ng the
image before printing. The out-of-gamut colors, or colors not reproduceable by
the ink and paper combination you have chosen for a print, will be displayed
with gray as a default, however one can view them in other colors by changing
this in the preferences. (See image on page 5 and “Softproof”, on page 27 for
more information.)
As this is truly an imperfect process, we are really learning to use its strengths
to our greatest advantage while simultaneously navigating the weaknesses
of the system. It is important to know that it is actually impossible for all the
colors viewed on a monitor to be identically matched in a print from a desktop
printer. There are many reasons for this. First, a printer operates in a CMYK
(cyan, magenta, yellow, black) color space, and a monitor operates in an RGB
(Red, Green, Blue) color space, each with entirely dif erent color gamuts. (See
“What is a color space?” on page 8 for more information.) Also, some colors
produced by printer inks cannot be displayed on a monitor, and some colors
that can be displayed on a monitor cannot be reproduced using inks on paper.
Paper surface types, such as glossy and matte, also have varying abilities to
reproduce color. Further, a monitor produces an image from an illuminated
light source, while a print is viewed by rel ected light. If the print will never
exactly match the monitor, than creating a good print may sound fairly
hopeless at this point.
However, this is precisely where the color management system i ts in, and
why it is so important. Since images come in from many dif erent devices,
color management helps you produce more consistent colors by creating
proi les (or, translators) to correctly transform and resolve color discrepancy
as an image travels from one space, or device, to another. This allows devices
to speak to one another in the same language of color. Colors in the
digital environment are described with a series of numeric values for each
corresponding color, and neutral. For example, middle gray can be described
numerically in the RGB space as 128 Red, 128 Green, and 128 Blue; similarly a