Computer monitors must be calibrated and profiled before they can be part of a professional workflow. Accurate monitor calibration and creation of a display profile requires a hardware device, such as the Gretag-MacBeth Eye-One, Color Vison Spyder2, or the Monaco Optix XR, still available from Color Gear. Another useful tool is a Profile Verification Kit (for instance, the one by Pixl Ltd). This is a digital file with an accompanying proof or print. After profiling your monitor, you view a comparison between the digital file, displayed in Photoshop (or other professional imaging software), and the proof print, as viewed under 5000K/D50 lighting, to indicate whether your monitor profile is accurate. If your work requires inkjet prints for display, you may do better to evaluate the images under 6500K/D65 lighting — and in some cases a dual-color viewing booth could be a useful investment.
Working Environment: No matter how good your monitor or how well you have it calibrated and profiled, you must take care that your working environment is subdued neutral lighting that does not vary throughout the day. Your computer desktop should be set to a neutral gray, and you should avoid having areas of bright color within your field of vision, or reflected in the monitor. This would include brightly colored clothing or brightly colored blinds, as any color reflected onto the screen is likely to influence your perception of the color it produces. If blocking off all windows in your editing room is not feasible or desirable, you can still achieve some measure of accuracy by creating a “daytime” profile and a “nighttime” profile, switching between the two.
Display Types: There are two types of display technology in use today: CRT and LCD. CRT (cathode ray tube W) displays are rapidly being replaced by LCD (liquid crystal display W) monitors. Professional grade CRTs such as the Sony Artisan are in fact no longer being made.
CRT monitors should be calibrated before they are profiled since they have hardware controls that alter the RGB amplifiers as well as controls for black level and luminance. The hardware device and software are used first to adjust the RGB guns to the desired white point W (often called color temperature W, although they are not quite the same concept) and black point (if available on your display system), and then the calibrated CRT is profiled. The display profile is then used by color-savvy programs such as Photoshop to display accurate color.
LCD displays often only have brightness controls, although some also have a contrast control. Some LCDs have color temperature controls, but these actually only adjust the CLUT (color look up table W), and if much different from the native color temperature, can cause reduced color gamut and banding. For that reason, when profiling an LCD, it is best to adjust only the brightness control and contrast control, and let the profiling device set the desired white point through the display profile.
Direct Digital Communication (DDC): DDC allows for the display’s brightness, contrast, white point and gamma to be adjusted through the profiling device and software. This will save time and improve precision when calibrating and profiling monitors. When shopping for a new monitor, its best to choose a DDC-compliant display if possible.
A good guide: Whether you use the Monaco Optix product or not, Monaco has an excellent PDF manual that explains in detail how to calibrate and profile both CRT and LCD monitors.
Choosing white point and gamma settings: The purpose of monitor calibration and profiling is to create a situation where the image on your monitor closely matches the image as it will appear on a print, a proof, a press sheet — or, if your work is destined for the web, as viewed on the average un-calibrated PC or Mac monitor. The white point may range from 5000K (yellow-red) to 6500K (bluer). The gamma correction W may vary from 1.0 to 3.0. The monitor’s luminance W may vary from 80 cd/m² to 140 cd/m². Adjust these settings based on viewing conditions. If comparing the monitor with proofs in a viewing booth, adjust to the best match. The correct luminance also depends on ambient light conditions. High-end color work should take place in ambient light controlled for color temperature, flare and luminance. For work in bright office or studio environments, you might need a luminance of more than 140 cd/m2 to see shadow detail on your monitor.
There is not a single standard for white point, gamma and luminance because there is not a single standard for what you are trying to match. If you are working in pre-press, you will want to match press proofs and press sheets. For this, you may find that a white point of 5000K or 5500K will give you the best match of monitor to proof or press sheet viewed under a 5000K light. The appropriate luminance may be around 100cd/m². If you are preparing files for ink-jet or Lightjet printing, you may find that a white point of 6000K or 6500K will give you the closest match, although you should always view the prints under the color temperature of the lighting that will be used to view them. Once again, monitor luminance should match the appearance of the display prints in the viewing condition. Prepared image files for the web on a monitor calibrated and profiled to the sRGB standard gamma of 2.2 and white point of 6500K. This will be a compromise between the uncalibrated Mac gamma standard of 1.8 and the uncalibrated PC standard of 2.4. It is also a reasonable compromise between a prepress monitor calibrated to 5000K and an uncalibrated PC monitor, which may be in the 7300K-9300K range. Modern LCD monitors usually have a native white point around 6500K.
Native white point: There is a good argument for keeping things simple with the current crop of LCD monitors: Profile using native color temperature and native gamma, and let your eyes adjust to the difference between the monitor and the print or proof. Doing so will ensure that you get the widest dynamic range the monitor can produce. It will also minimize artifacts, banding and posterization, which become more noticeable as you force a monitor (especially an 8-bit monitor) farther from its native white point and gamma. If you do choose a custom white point and gamma, it is a good idea to evaluate the resulting profile with a utility such as Dry Creek Photo’s Black Point Check and Grayscale Test.
More about gamma: There are more choices for gamma than 1.8 and 2.2. Some calibration software allows you to choose a custom gamma. Other software allows you to edit the gamma curve, and one product, Integrated Color’s ColorEyes Display, has “L* gamma,” which creates separate tonal curves for the shadow areas, mid-tones, and highlights. It is said to provide smoother transitions, and therefore more accurate color reproduction. If you are working in Adobe Photoshop, monitor gamma will not affect the appearance of image files, since Photoshop automatically corrects the gamma of the image as it is displayed on the monitor. Choosing a gamma has more to do with allowing your monitor to operate in its particular sweet spot, and avoid loss of gamut, banding or posterization that may appear if you force it to run too far from its native gamma.
Monitors of the future: The current LCD technology uses a white fluorescent backlight. NEC has produced a new type of LCD that uses red, green and blue LEDs (light emitting diodes) that combine to produce a white backlight. The advantages are a wider color gamut, greater dynamic range, and the ability to adjust the white point without compressing the color gamut. The NEC MultiSync LCD2180WG-LED is the first commercially available monitor of this kind.