Important: The following terms and concepts are used throughout this document. You should review them first.
Terms and concepts
Mac OS X automatically generates two types of information relevant to ColorSync setup when you start up a computer. This is done for any connected display, such as an Apple Cinema Display or built-in PowerBook LCD display, that broadcasts self-descriptive data using the EDID protocol. Current Apple displays and most third-party displays transmit this information.
First, Mac OS X makes a list of all displays connected to your computer. Each list entity, which will later appear as a menu selection, is a known as a display device or device name. This device name is actually derived from information permanently stored in the display hardware itself. Examples of device names are "Studio Display 21" and "Color LCD".
Second, Mac OS X generates a ColorSync profile to be associated with the display device. The profile includes a description of the display's color reproduction characteristics, and it is also created using information that is permanently stored in the display hardware itself. You may change the profile associated with a display device at a later time. Profiles are stored on the hard disk at: /System/Library/ColorSync/Profiles/Displays/
The profile that is generated at startup shares the same name as the device name. When making menu selections, it is important to remember that these are two different software entities. The Display pop-up menu, discussed below, is an example of where both display devices and profiles appear in the same place.
The term Displays pane always refers to what you can access by choosing Displays from the View menu while in the System Preferences application.
The term ColorSync pane always refers to what you can access by choosing ColorSync from the View menu while in the System Preferences application. To see the Display pop-up menu, click the Device Profiles tab.
About ColorSync and Displays panes
Display may seem to have three names
For each display, there is a device name, a profile that has the same name by default, and a profile filename. The profile name is what you see in system and program menus, while the profile's filename contains the ".icc" extension and may be seen as part of a full pathname. Holding the mouse pointer still over any of the pop-up menus in the ColorSync pane of System Preferences brings up Help text showing the name of the display device, profile name, and profile pathname (Figure 1); or it may simply show the path to a specific profile (Figure 2). This can help you determine if the current setting is a display device or a profile.
Figure 1 Device name, profile name, and profile pathname
Figure 2 Profile pathname
Difference between the ColorSync pane and Displays pane
The Displays pane includes a wide range of settings, including geometry, arrangement, resolution and color depth. You can make display-specific color adjustments in the Displays pane , including the assignment of a ColorSync profile to a display device, but it does not encompass the entire color management process. When you select the Displays pane, a System Preferences window appears on each connected display. This clearly identifies which display you are adjusting.
The ColorSync pane focuses on the entire color management process, and it does not include the general, noncolor display settings.
ColorSync functions included in the Displays pane of System Preferences
Here you can assign a different ColorSync profile to each display. You can do the same thing and more using the ColorSync Utility (located at /Applications/Utilities/).
Functions of the ColorSync pane
The ColorSync pane of System Preference gives you control over the entire color management process, including the ability to:
The ColorSync pane provides choices that are not available in the Displays pane
Setting the "system profile"
The Display pop-up menu in the ColorSync pane determines what is used as the system profile. This is what Mac OS X returns to an application that requests the "system profile." Here you may choose from two different types of entities: display devices and ColorSync profiles. If you choose a display device here (which is the default choice), then the system profile returned to requesting applications is the one selected for that display device in the Displays pane. If you choose a ColorSync profile here, then it is used as the system profile. See below for more information on this behavior.
How to determine which profile is authoritative if the system profile and individual displays are all assigned different profiles
When the system profile and individual display profiles do not match, behavior varies with different types of applications. Individual applications have different ways of indicating to you which profile is in use. You can experiment to see what happens and what works best for you. See the documentation or help files included with your application. Cocoa applications only use the preferred display device's profile, or "system profile." For most predictable results, set the Display pop-up menu to a device name and choose the profile in the Displays pane. This is not a concern for most users, who have one display and use the default profile.
If you have one display
By default, your display is the only designated display device, and its profile is the one automatically generated when you started up the computer. You do not need to change any settings. However, if you want to create a new profile or change its profile, use the Displays pane of System Preferences. Alternatively, you may go directly to the Display Calibrator application located in the Utilities folder (/Applications/Utilities/).
Terms and concepts
Mac OS X automatically generates two types of information relevant to ColorSync setup when you start up a computer. This is done for any connected display, such as an Apple Cinema Display or built-in PowerBook LCD display, that broadcasts self-descriptive data using the EDID protocol. Current Apple displays and most third-party displays transmit this information.
First, Mac OS X makes a list of all displays connected to your computer. Each list entity, which will later appear as a menu selection, is a known as a display device or device name. This device name is actually derived from information permanently stored in the display hardware itself. Examples of device names are "Studio Display 21" and "Color LCD".
Second, Mac OS X generates a ColorSync profile to be associated with the display device. The profile includes a description of the display's color reproduction characteristics, and it is also created using information that is permanently stored in the display hardware itself. You may change the profile associated with a display device at a later time. Profiles are stored on the hard disk at: /System/Library/ColorSync/Profiles/Displays/
The profile that is generated at startup shares the same name as the device name. When making menu selections, it is important to remember that these are two different software entities. The Display pop-up menu, discussed below, is an example of where both display devices and profiles appear in the same place.
The term Displays pane always refers to what you can access by choosing Displays from the View menu while in the System Preferences application.
The term ColorSync pane always refers to what you can access by choosing ColorSync from the View menu while in the System Preferences application. To see the Display pop-up menu, click the Device Profiles tab.
About ColorSync and Displays panes
Display may seem to have three names
For each display, there is a device name, a profile that has the same name by default, and a profile filename. The profile name is what you see in system and program menus, while the profile's filename contains the ".icc" extension and may be seen as part of a full pathname. Holding the mouse pointer still over any of the pop-up menus in the ColorSync pane of System Preferences brings up Help text showing the name of the display device, profile name, and profile pathname (Figure 1); or it may simply show the path to a specific profile (Figure 2). This can help you determine if the current setting is a display device or a profile.
Figure 1 Device name, profile name, and profile pathname
Figure 2 Profile pathname
Difference between the ColorSync pane and Displays pane
The Displays pane includes a wide range of settings, including geometry, arrangement, resolution and color depth. You can make display-specific color adjustments in the Displays pane , including the assignment of a ColorSync profile to a display device, but it does not encompass the entire color management process. When you select the Displays pane, a System Preferences window appears on each connected display. This clearly identifies which display you are adjusting.
The ColorSync pane focuses on the entire color management process, and it does not include the general, noncolor display settings.
ColorSync functions included in the Displays pane of System Preferences
Here you can assign a different ColorSync profile to each display. You can do the same thing and more using the ColorSync Utility (located at /Applications/Utilities/).
Functions of the ColorSync pane
The ColorSync pane of System Preference gives you control over the entire color management process, including the ability to:
- set default profiles for input, display, output, and proofing devices
- set default profiles for document color spaces, including RGB, CMYK, Gray, and Lab (and you can programmatically set a default profile for XYZ space)
- select a preferred CMM
- save these color settings in named "workflows" and switch between them
The ColorSync pane provides choices that are not available in the Displays pane
Setting the "system profile"
The Display pop-up menu in the ColorSync pane determines what is used as the system profile. This is what Mac OS X returns to an application that requests the "system profile." Here you may choose from two different types of entities: display devices and ColorSync profiles. If you choose a display device here (which is the default choice), then the system profile returned to requesting applications is the one selected for that display device in the Displays pane. If you choose a ColorSync profile here, then it is used as the system profile. See below for more information on this behavior.
How to determine which profile is authoritative if the system profile and individual displays are all assigned different profiles
When the system profile and individual display profiles do not match, behavior varies with different types of applications. Individual applications have different ways of indicating to you which profile is in use. You can experiment to see what happens and what works best for you. See the documentation or help files included with your application. Cocoa applications only use the preferred display device's profile, or "system profile." For most predictable results, set the Display pop-up menu to a device name and choose the profile in the Displays pane. This is not a concern for most users, who have one display and use the default profile.
If you have one display
By default, your display is the only designated display device, and its profile is the one automatically generated when you started up the computer. You do not need to change any settings. However, if you want to create a new profile or change its profile, use the Displays pane of System Preferences. Alternatively, you may go directly to the Display Calibrator application located in the Utilities folder (/Applications/Utilities/).