Selecting working color space in PhotoShop
PhotoShop created quite a stir in the Graphic Arts /
Prepress community when it selected the smaller sRGB as the
default colorspace when introducing the color management
concept to the product in version 5. Files created in
version 4 using the Radius PressView ColorMatch 5000K / 1.8
gamma conditions looked completely different when open in
PhotoShop 5. Things settled down a bit once designers and
publishers learned how to use the ICC profiles and color
management tools introduced in version 5.
sRGB is also the default setting in version 6. This
seems to make little sense given the overwhelming
advantanges of using the larger Adobe RGB (1998) gamut and
the fact that Adobe is promoting it as a new publishing
industry standard. The selection of sRGB as the default when
PhotoShop is installed reflects the reality that most of its
users now create content for the Web rather than print.
Besides, those who do create CYMK files understand color
management and how to change the default RGB color space
PhotoShop uses when an unprofiled file is opened. To make
the selection for color space for web and print easier
PhotoShop version 6 allows the user to easily select one
of two "standard" profiles: "U.S. Prepress Defaults" and
"Web Graphics Defaults" using the Edit > Color Settings menu.
The "Web Graphics Default" color setting in PhotoShop uses sRGB
IEC61966-2.1 as the RGB working space and U.S. Coated SWOP v2 and the CYMK
working space. These defaults are appropriate if the file will be used only on
the web, but as noted above the manner in which the limited RGB gamut is mapped
to CYMK puts serious limitations on the color gamut for files which are printed.
For example, see the attached comparison of sRBG vs the Epson1200 printer ink set.
The "U.S. Prepress Default" color setting in PhotoShop uses Adobe
RGB (1998) as the RGB working space and U.S. Coated SWOP v2 and its CYMK working
space. Adobe RGB (1998) has a white point of 6500 K and a gamma of 2.2 and is
able to convert to CYMK for printing with very little clipping or remapping of
color when printed or converted to sRGB. For example, see the attached comparison of Adobe RGB
(1998) vs the Epson1200 printer ink set.
You can, and should, select one or the other of these two
default modes before opening and resaving a camera file.
This is done via the Edit > Color Settings menu. Be sure to
use "Save As" to save a copy, rather than overwriting the
original camera file. Retaining the unaltered camera file
will allow it to be later opened for printing using U.S.
Prepress defaults Embed the profiles when saving the files.
If you print and post to the web but only want to save one
version of the edited file, open and save the camera file
with the larger Adobe RGB gamut embedded. It can be later
be opened and remapped into the smaller sRGB gamut if
required.
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