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To get prints that match your screen, you’ll need:

• a monitor profile of your display
• an accurate printer profile
• images in a known standard color working space

In this article we’ll discuss the first step, what you need to make a monitor profile and how to make it. In a future article we’ll discuss printer profiles and standard working spaces. For now, suffice it to say that to make your own printer profiles, you’ll need a more expensive instrument and software program. You may be able to save the expense if you use a popular printer and media for which the manufacturer offers accurate profiles. Many media manufacturers post profiles on their web sites.

We’ll also discuss standard color working spaces later. The point is, you should know where your files are coming from. If you get a file from someone, or open one that you saved some time ago, the standard working space profile should be embedded in it, otherwise you won’t know how it was last saved. The file may not display the same as it did before.

Monitor Calibration Systems
Although the Adobe Gamma (Mac/Win) and Apple Display System Preference (Mac OS X) can be used to visually calibrate a monitor, it’s more accurate to use a color measurement instrument. Specifically, you need an emissive colorimeter that can read color values from a monitor.

Three leading monitor calibration systems are GretagMacbeth’s i1 Display (www.i1color.com), Monaco’s Optix (www.monacosys.com), and ColorVision’s Spyder (www.colorvision.com). These systems include an emissive colorimeter and monitor calibration software.

Calibrating Your Monitor
Calibration, one of the “4 Cs” of color management, means achieving a known standard of performance. For monitors, the standards are contrast (gamma) and color balance (white point).

Gamma is measured on a scale of 1.00­2.40, where higher values are darker. Apple established a gamma of 1.80 for Macintosh, while Microsoft uses 2.20 for Windows. Either gamma setting can be used on either platform, as long as you’re consistent.

White point is measured on a scale of 5000-9300 Kelvin. Lower values are more reddish; higher, more bluish. Graphic arts users who plan to print on offset presses prefer to use 5000 K, as this coincides with the ISO standard viewing standard for the graphic arts. Some users find that 5000 K is too warm, and prefer to use a higher setting like 5500 or 6500. They cite the fact that viewing standards were written for fluorescent light bulbs, and monitors are generally dimmer. For graphic arts, you may want to pick a color temperature that makes the monitor’s white balance match the printing paper used.

Monitor calibration creates a curve that is downloaded to the computer’s video card and gives the monitor the specified value. These calibration curves are stored in the monitor’s ICC profile. On Windows, the calibration curves are downloaded to the video card upon startup. If you switch profiles, the display won’t change, as the new calibration curves won’t be loaded until you restart the computer. Macintoshes dynamically load calibration curves when monitor profiles are selected. When you select a new profile, the display’s contrast and color balance will change.

Optimizing Your Monitor
Most monitor calibration programs help you to set the monitor’s hardware or software controls to values close to your calibration aimpoints. This step is known as optimization or, to fit within the “4 Cs,” consistency. Assume you want to calibrate your monitor to 6500 K. Your monitor has hardware controls enabling you to set 5000, 6500, and 9300 K. You’d want to set it to 6500 K with the hardware controls so the calibration curve won’t need to correct the display as much as it would for a 9300 K starting point. If the monitor doesn’t need to be corrected as much, the calibration may be more accurate, and it may remain more accurate over time.

To understand the value of monitor optimization, consider two extremes. Let’s say you have a CRT monitor that’s over ten years old. Due to fading of the phosphors, it’s so dim that you can hardly see anything on the display. A monitor calibration program probably won’t be able to calibrate this monitor, as there isn’t enough brightness and contrast. The other extreme, which is harder to find, would be if the monitor is too bright or contrasty to calibrate. This might occur if a circuit in the video card or monitor was faulty. In any case, the monitor calibration program wouldn’t be able to calibrate this monitor either. These extremes point out the value of optimization: to have your monitor aligned as close as possible to your intended calibration values.

Some users become obsessed with monitor optimization, confusing the software tools for setting the monitor with the actual calibration process. As long as the monitor falls within reasonable contrast and color balance ranges, your color management program should be able to calibrate it. For example, assume you want to calibrate to 6500 K. The optimization routine indicates that your monitor’s 6500-K preset is actually 6700 K. This value is probably close enough to calibrate.

The Monitor Profile
After performing the optimization and calibrating to the set gamma and white point, monitor calibration programs then make an ICC profile of the monitor, which should be set as the standard monitor profile. This is the third step in the “4 Cs,” characterization.

When it’s time to save your monitor profile, a naming convention will help you keep track of your profiles, settings, and dates. A good way to name profiles is the monitor name, calibration values, and creation date. For example, if you have a Sony monitor calibrated to 6500 K and gamma 1.80, made on June 11, 2004, you could name it “Sony_D65G180_061104.icc.”

Color Conversion
The reason you’re going to all this trouble of optimizing, calibrating, and profiling your monitor is so that “what you see is what’s in the file” (WYSIWIF). To do this, your color application must convert (the fourth and last “C”) from the file’s standard working space (e.g., Adobe RGB or sRGB) to your monitor profile. Display conversion is automatically done by graphics applications that are ICC compliant, including those from Adobe and Quark.

Advanced Monitor Calibration Features
GretagMacbeth sells two versions of its i1 Display package. Both come with the i1 Display emissive colorimeter. The i1 Display basic package includes the i1 Match software which optimizes, calibrates, and profiles monitors. The more advanced i1 Display PM comes with the ProfileMaker software which has several advanced features. To understand the value of these advanced features, consider the following scenario:

• You have a studio with 3 monitors, including a mixture of CRTs and LCDs.
• You work with print, where you’re comparing screen previews to printed samples.

Paper white point. If you work in graphic arts, having the white on your monitor match your printing paper may be a useful feature. With ProfileMaker, you can enter the paper’s colorimetric readings and set the monitor’s white point to that of the paper. (To actually read the paper, you would need a spectrophotometer such as GretagMacbeth’s i1 Photo.)

Luminance adjustment. If your studio has several monitors and you want them all to have the same brightness, then the ability to set monitor luminance quantitatively may be valuable. Keep in mind that if you have three monitors that are all profiled, the same image when viewed simultaneously on all monitors should match, at least to the best of the monitors’ capabilities. However, the monitors’ brightness levels and background may look different. ProfileMaker lets you adjust monitor luminance in candelas per square meter (cd/m2) so that multiple monitors can be set to the same brightness.

Network monitor calibration. Again, assume you have the same image displayed on three calibrated monitors. The images should look more or less the same, but may look slightly different if the monitors have different color gamuts. Network monitor calibration lets you pick one monitor as the studio “standard,” save its calibration values, and use these values as a standard for the other monitors. This ensures closer matching on multiple machines. Network monitor calibration is also useful for remote proofing, where someone at another location will be viewing your files and wants their monitor to have the closest possible appearance to theirs.

Profiling dual displays. Many people use more than one monitor on the same computer. Remember that monitor calibration values are stored in the video card, so if your video card only supports calibration of one monitor, you can only calibrate one of the displays. Most users calibrate one color-critical monitor and use the uncalibrated monitor for tool palettes. If you want to calibrate both displays, you’ll need (1) a separate video card for each monitor, or (2) a video card that supports calibration of multiple displays. Such video cards are available from Matrox (www.matrox.com) and ATI (www.ati.com).