Color Management
Understanding Color Management
Each device has a range of colors, or color space, that it uses. For example, a monitor displays a different set of colors than a printer reproduces. Because of this, some colors may be seen on the screen that cannot be printed. This is referred to as the color gamut.
A color management system can be used to translate colors from one device to another. Color profiles define the color space for the monitor and for the input and output devices in use.
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Choosing Color Profiles
Different brands and models of monitors, scanners, digital cameras, and printers have different color spaces, and thus require different color profiles. Some widely used profiles are installed with CorelDRAW Graphics Suite 12.
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Choosing Advanced Color Management Settings
After color profiles have been chosen, the color management system uses a Color Matching Module (CMM) to match colors between devices as closely as possible. CorelDRAW 12 uses the Kodak® Color Management System by default. Different rendering intents can also be selected, which control how the color management system converts colors between different color spaces.
When graphics are imported or exported, color profiles can be embedded or attached. By embedding a color profile, color integrity will be ensured; anyone viewing or printing your work will use the same profile.
By enabling the gamut alarm, on screen colors cannot be printed can be previewed. The colors that cannot be reproduced are highlighted (by default the highlighting color is green).
Embedded color profiles take into account the different color gamuts that exist and provide cross platform communication of the different color spaces. A color profile is a description of a device's color handling capabilities and characteristics. An embedded color profile is a color profile, attached to or embedded into a color document. It describes the color space of the color contained within the document. Corel supports ICC embedded profiles. This allows the same color profile to be communicated across platforms, and ensures accurate color management throughout the publishing process. Embedded color profiles ensure accurate color reproduction between the input (scanner) and the output (printer) device. The ability to embed ICC profiles into many file formats, including CorelDRAW .CDR and .CPT formats, allows for consistent color spaces between all applications that support ICC profiles.
Use Color profiles to correct on screen colors so that each color displays as accurately as possible based on its color value. Color profiles can display colors on screen as they will appear when they are printed. Proper color profiles can also warn when a selected color is outside your printer's color gamut. Accurate color profiles of your scanner, monitor, and printer make is possible for colors to be corrected so the color seen on the screen matches the color in the final output.
Color profiles can be embedded in a file at the time of saving from CorelDRAW 12 or Corel PHOTO-PAINT 12 by selecting the Embed ICC profile option. Profiles will be recognized when the file is later opened by programs that support embedded ICC profiles.
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Understanding the Color Management Dialog Box
Color management is the process of matching colors between devices, such as scanners, digital cameras, printers, and monitors. CorelDRAW includes color management controls designed to help you achieve the best possible color matches by allowing individual profiles to be assigned to each available device.
Many of the icons shown (Monitor icon, CMYK Printer icon, Import/Export icon, Offset Separations icon and Internal RGB icon) when clicked directly will allow color management options and advanced settings to be specified.
The pull-down located under the icons allow one to choose color profiles for each device. Color profiles can be obtained from the application CD or from the device's manufacturer's Web site. To help choose the appropriate profile, consult the manufacturer's documentation for the specific device or contact the device manufacturer directly.
Clicking the arrows turns color profiles for devices on or off and determine which settings are to be used. The arrows appear orange when on, and grayed and broken when off. You can use the arrows to correct colors between devices, and control how colors are displayed.
When a device is corrected for color, at least two profiles are used, one for each device. For example, if the printer colors are being corrected using Internal RGB, both the Internal RGB and CMYK Printer profiles are used. If simulation is used to display colors on the monitor as they are printed, three profiles are used: the Internal RGB, CMYK Printer, and Monitor profiles.
In the Color Management dialog box, the following visual elements can be activated:
Scanner/Digital Camera
Represents a scanner and/or digital camera.
Separations Printer
Opens the Advanced printer settings dialog box, which allows users to link a color profile to a separations printer.
Monitor
Opens the Advanced display settings dialog box, which allows users to choose settings for the out of gamut warning color and mapping colors into CMYK gamut.
Composite Printer
Opens the Advanced printer settings dialog box, which allows users to link a color profile.
Import/Export
Opens the Advanced import/export settings dialog box, which allows users to choose import and export options for profiles.
Internal RGB
Opens the Advanced settings dialog box, which allow users to choose Rendering Intent and color engine settings
Arrows
Allows users to correct colors between devices, and to control how colors are displayed. The arrows appear orange when on, and grayed out and broken when off.
The following table contains descriptions of what settings are applied when an arrow is on or off:
| Arrow |
On |
Off |
| From the scanner/digital camera to Internal RGB |
The scanner/digital camera profile and the Internal RGB profiles are used for color correction |
The profiles are not used |
| From Internal RGB to the Monitor |
The colors are calibrated for display using the Internal RGB and monitor color profiles |
The profile is not used |
| From Internal RGB to the Composite printer |
The printer and Internal RGB profile are used for color correction |
The profile is not used |
| From the Composite printer to the monitor |
The monitor simulates a composite printer output |
The monitor does not simulate a composite printer output |
| From Internal RGB to the Separations printer |
The separations printer and Internal RGB profiles are used for color correction |
The profile is not used. You can override this setting in the Print dialog box. |
| From the Separations printer to the Monitor |
The monitor simulates color separations printer output |
The monitor does not simulate color separations printer output |
| From the Separations printer to the Composite printer |
The composite printer simulates separations printer display |
The composite printer does not simulate separations printer display |
| From Internal RGB to Import/Export |
Internal RGB profiles are embedded |
The profiles are not embedded |
| From Import/Export to Internal RGB |
Embedded ICC profiles are used |
ICC profiles are ignored |
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Working with Color Profiles
A color management system helps to achieve accurate colors across a variety of devices consistently. The first stage in setting up a color management system is to choose color profiles for the monitor and each of the devices to be used, such as scanners, digital cameras, and printers.
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Calibrating Your Equipment
It is equally important that you calibrate your devices before working on a project in order to achieve color consistency.
Calibrating Your Monitor
Calibration refers to the process of building a profile for your monitor, so it's particular color characteristics are captured for use by a color management system. After calibrating your monitor, you know what it's color space limits are and what colors you expect it to produce. All monitors respond differently to the same electronic information. Two identical monitors from the same manufacturer responds differently and display slightly different colors on screen when provided with the identical color file. This is due to a number of factors such as monitor age, ambient lighting, or monitor settings. To achieve consistent color reproduction, it is recommended that you calibrate your monitor and be aware of factors that can affect your monitor's performance.
Use the following recommendations to aid in achieving accurate color reproduction in your projects:
- Warm up your monitor for up to one hour before beginning calibration.
- Clean your monitor screen before beginning calibration.
- Manually adjust your monitor controls and tape them down so they are not accidentally readjusted after system calibration.
- Calibrate your monitor on a regular basis, especially if it is an older monitor because phosphors fade over time.
- Have consistent lighting, Each type of lighting including, fluorescent, incandescent, and natural, will affect the colors you see displayed on your monitor. Avoid natural light as much as possible since this changes constantly throughout the day. Consider having grid diffusers installed over fluorescent lighting.
- Use a neutral background on your monitor and for your work area to avoid influencing your perception of colors.
- Take breaks. Give your eyes a rest throughout your work period. Take the time to look away from your monitor to avoid eye strain and fatigue.
- If you view your work on more than one monitor, make sure they are all set at the same white point.
- Use monitor profile building software to build a profile for your monitor.
Calibrating Your Scanner
Perform scanner calibration every month or so, depending on use. Scanner bulbs change color with age, affecting the color of your scans. Keep the glass clean to improve scanning quality.
There are several tools available for scanner calibration.
All of them use the same basic technique: place a known source image on the scanner, scan the image, and look at the colors recorded. Knowing what the values of the colors should be and comparing them to the colors scanned, build a profile that corrects the scanner to produce the right colors. Refer to the accessories that came with your software or your scanner for more information. After you have made your profile, you set it as your Scanner profile.
Calibrating Your Printer
Color from printers can vary widely, from day to day, from printer to printer, and from one set of inks or color sheets to another or by the paper used. Inkjet printers, for example, take a wide variety of papers: plain copy paper, coated paper, glossy paper, and many other types of paper. The interaction between the inks and the paper affects the resulting colors. To ensure accurate color, create a profile for each combination of media (inks, paper, ect.), and update the profiles as conditions change. Printers age with time, and this, too, can cause colors to shift. Updating profiles periodically will ensure your printer colors are as accurate as possible.
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