Calibrating your display

Calibrating your display

Display types


Th ere are two main types of computer displays: a CRT (cathode ray tube, as in a traditional TV set) and the more common LCD (liquid crystal display,or fl at panel display). Th e display performance of a CRT fl uctuates due to its analog technology and the fact that its display phosphors (which produce the glowing dots that you see onscreen) fade over time. A CRT display can be calibrated reliably for
only around three years.
LCD displays use a grid of fi xed-sized liquid crystals that fi lter color coming from a back light source. Although you can adjust only the brightness on an LCD (not the contrast), the LCD digital technology off ers more reliable color consistency than a CRT, without the characteristic fl ickering of a CRT. Th e newest LCD models provide good viewing angles, display accurate color, use the desired daylight temperature of 6500K for the white point (see below), and are produced under tighter manufacturing standards than CRTs. Moreover, the color profi le that’s provided with an LCD display (and that is installed in your system automatically) usually describes the display characteristics accurately.

➤ Both types of displays lose calibration gradually, and you may not notice the change until the colors are way off . To maintain the color consistency of your display, stick to a regular monthly calibration schedule. Thankfully,our calibration software reminds us to recalibrate our display via a monthly onscreen alert.


Understanding the calibration settings

 Th ree basic characteristics are adjusted when a display is calibrated: Th e brightness (white level) is set to a consistent working standard; the contrast (dark level) is set to the maximum value; and a neutral gray (gray level) is established using equal values of R, G, and B. To adjust these characteristics,calibration devices evaluate the white point,black point, and gamma in the display.

➤ Th e white point data enables the display to project a pure white, which matches
an industry-standard color temperature.Photographers favor using D65/6500K as the
temperature setting for the white point.

➤ Th e black point is the darkest black a display can project. All other dark shades are lighter than this darkest black, which ensures that shadow details display properly.

➤ Th e gamma defi nes how midtones are displayed onscreen. A gamma setting of 1.0 reproduces the linear brightness scale that is found in nature. Human vision, however, responds to brightness in a nonlinear fashion, so this setting makes the screen look washed out. A higher gamma setting redistributes more of the midtones into the dark range, which our eyes are more sensitive to, and produces a more natural-looking image. Photography experts recommend using a gamma setting of 2.2 for both Windows and Macintosh displays.


Buying a calibration device

Th e only way to calibrate a display properly is by using a hardware calibration device, which produces a profi le containing the proper white point,black point, and gamma settings for your display.Th e Adobe color management system, in turn, will use that profi le to display colors in your Photoshop document more accurately.
If you’re shopping for a calibration device,you’ll notice a wide range in cost, from a $100 to $300 colorimeter to a much more costly, but more precise, high-end professional gadget, such as a spectrophotometer. A colorimeter and its stepby-step wizard tutorial will enab e you to calibrate your display more precisely than you could by using subjective “eyeball” judgments. Among moderately priced calibrators, our informal reading of hardware reviews and other industry publications has yielded the following as some of the current favorites: Spyder3Pro and Spyder3Elite by Datacolor; i1 Display 2 and i1 Display LT by X-Rite; and hueyPro, which was
developed jointly by PANTONE and X-Rite.
Note: If, after calibrating your display, you intentionally or unintentionally adjust the display’s brightness and contrast settings or change the room lighting (or repaint your walls!), remember to recalibrate it!
For Mac OS users who don’t have a calibration device, your system supplies a display calibration utility; look for it in System Preferences > Displays > Color. Click Calibrate and follow the instructions that appear onscreen.


Th e steps outlined here apply loosely to the three hardware display calibrators that are mentioned on the preceding page. We happen to use Spyder3Pro.


To calibrate your display using a hardware device:

1. Set the room lighting to the level that you normally use for work. If you have a CRT, let it warm up for 30 minutes for the display to stabilize.

2. Increase the brightness of your display to its highest level. In the Mac OS, if you have an Apple display, choose System Preferences > Displays and drag the Brightness slider to the far right. For a third-party display or any Windows display, use either a mechanical button on the display or a menu command in the OnScreen Display (OSD).

3. Launch the calibration application that you’ve installed, then follow the straightforward instructions on the step-by-step wizard screens.A–B You will need to tell the application the following important information: your display type (CRT or LCD), the white point to be used (choose D65/6500K), and the desired gamma value
(choose 2.2 for both Windows and Macintosh).
For a CRT display, you may see a few more instructional screens requesting further display setting choices.

4. After entering your display information (A,next page), you’ll be prompted to drape the colorimeter(hardware calibration sensor) over the monitor (B, next page). For an LCD, if a baffl e is included with the calibration device, clip it on to prevent the suction cups from touching and potentially damaging the screen. Follow the instructions to align the sensor with the image onscreen. Click OK or Continue to initiate the series of calibration tests, which will take from 5 to 8 minutes.


5. After removing the calibration sensor, you’ll be prompted to name your new display profi le (C, next page). Include the date in the profi le name, for your own reference. Th e application will place the new profi le in the correct location
for your Windows or Macintosh operating system. Th e wizard will step you through one or two more screens, and then you’re done. When launched, Photoshop will automatically be aware of the new display profile.




 

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