re: the basic idea of color profiles
re: the basic idea of color profiles
- Subject: re: the basic idea of color profiles
- From: AJ Dumas <email@hidden>
- Date: Mon, 25 Mar 2002 15:21:13 -0600
Following is a text file I made while trying to figure out ColorSync after
our firm purchased a new Xerox Phaser 790 a month ago. I For several days I
struggled with trying to understand all of this, at least enough to get
quality ouput from the printer (which it definitely did NOT do after initial
setup). After many calls to Xerox, visits to Apple.com/colorsync, a few
trips to the archives of this list, reading thru Adobe software manuals,
etc. I finally came up with this text file that I feel explains what is
going on with my workflow as far as ColorSync is concerned. If anyone can
find fault with my outline/theory/understanding - please let me know. One
thing that was "breakthrough" for me to understanding all of this, was my
idea of a "dual track" in color mgmt (see below).
I am a novice to color mgmt, I'm just posting this to see if 1) it is indeed
a fairly accurate understanding, 2) help anyone else who might be struggling
similarily. I apologize in advance for the length.
--
Aj Dumas
Partners in Design
A R C H I T E C T S
COLORSYNC INFO
Color Management is a complex subject and can be quite confusing. However,
it is becoming more necessary in order to produce great color results. The
following is my understanding of the subject based on the use of Macintosh
and the Xerox Phaser 790 Color Laser Printer.
PROFILE SELECTION vs PROFILE CREATION
There is a definite difference between selection and creation of profiles.
There are many pre-built profiles from many different sources (Apple, Adobe,
manufacturers, etc.). In addition to these pre-built solutions, profiles can
be created from scratch with special hardware/software or pre-built profiles
can be modified (or "calibrated") to match specific pieces of equipment with
software such as the control panels Adobe Gamma or Monitors>Color>Calibrate.
A pre-built or modified profile can be selected and applied using either
ColorSync, Monitors>Color or Adobe Gamma control panels. The control panels
all talk to each other - once a profile is selected in one control panel, it
is reflected in the others.
NOTE: profiles set in the ColorSync control panel will be used only when no
profile is embedded in a file or chosen in an application or driver.
Below is an order of workflow where color profiles could impact final
output.
DUAL TRACK
This idea is extremely important to my understanding of Color Mgmt. There
are really two tracks to how color is managed from Input to Output. The
first track (Image Track) has to do with the image itself and its path
through my system workflow. The second track (Monitor Track) is the monitor
that displays the image along the way. These two tracks are separate from
each other, but obviously the monitor track effects my judgement of what
will be output from the printer.
++ IMAGE TRACK ++
INPUT
A pre-built RGB profile could be obtained from hardware manufacturers of
equipment such as scanners or digital cameras. Without pre-built profiles
from the manufacturers of each device or hardware/software to create a
custom profile, the best choice seems to be to use the pre-built "Generic"
profile provided by Apple with the Mac OS. Another option is to use what is
becoming the standard color space, sRGB. Many manufacturers are already
using this as the default profile. If the ColorSync control panel is set to
use sRGB, then scans done on the Mac would match scans done on the Wintel -
theoretically.
In the PID (and MED) workflow, it is not viewed as being critical to match
the original (scan or picture). It is more important to have the output
match the monitor, since any important images would be edited prior to
output and if I like what I edit on the screen, I really don't care too much
about what the original looks like (as long as I get as much color info from
the original as possible).
Conclusion: use Generic RGB (Apple) or sRGB upon capture (this may be
automatically selected by the device).
FILE
Upon initial capture of the image, it can be embedded with the profile of
the capture device (scanner, digital camera, etc.). Doing this will keep the
colors more accurate to the original as the image file moves through the
workflow because the color space of the original is a known and predictable
element. Without embedding this, the first application that opens the file
will either ignore color mgmt (if set to do this) or make a generic
assumption when converting the image file to the working color space of the
application.
Conclusion: do NOT embed a profile.
APPLICATION
The software the file ends up going into first (and thereafter) will have
options to both Convert and Embed a color profile. The theory on this is
that by embedding the profile it will better survive the process of moving
from app to app and finally to output. However, if all of the apps in the
process are set to convert to the same color profile work space, then there
would appear to be no reason to embed the profile. The only situation might
be where files are sent out of the office.
With this in mind, the idea would be in the Apps to either convert to the
color space of the output device (IE. EFIRGB & Fiery ColorCopy) or to the
emerging standard sRGB. The world of digital imaging may be moving to sRGB,
but considering it has such a narrow color space, I think that the output
device should be used instead.
Conclusion: use EFIRGB & Fiery ColorCopy and do NOT embed the profile unless
outsourcing the file for output.
OUTPUT
Obviously, it is important to have a profile that matches the color space of
the output device. The benefit of using the profile for the output device in
the Application's working color space is that there is minimal conversion
upon printing. This one is a no-brainer, use the output device profiles
during printing (via the Printer Driver).
Conclusion: use EFIRGB (for RGB) & Fiery ColorCopy (for CMYK)
++ MONITOR TRACK ++
MONITOR/DISPLAY
The monitor profile is like a filter that the images are viewed thru. This
filter (profile) knows the color space the monitor was built with and by
calibrating the profile, it knows the current real-world capabilities. By
having this profile, the images can more accurately be displayed. This RGB
profile will describe the monitor that I view my files on. There are a
couple of big questions regarding this profile...
1) Do I use the profile for the monitor (Apple MultiScan 1705) or for the
output device (EFIRGB)?
Refer to the Dual Track paragraph above. Since the monitor profile is just a
"filter" and does not directly influence the image file, use the
manufacturer profile for the monitor.
2) Do I use the pre-built profile or do I modify/calibrate it?
Definitely calibrate the monitor so that it gives the best representation of
the image onscreen.
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.