The Critically Important Color and Gamma Calibration Article
This article will explain how to understand and work with Photoshop's Color Management System (CMS), including how to create a custom profile, how to create an ICC profile for a monitor, how to set Photoshop's CMS defaults, how to use the Color Settings dialog box, and much more. It is excerpted from Inside Photoshop CS, by Gary D. Bouton. (Sams, 2004, ISBN: 0672326442).
The Critically Important Color and Gamma Calibration Article - Preparing to Create a Custom Profile (Page 5 of 16 )
Before we start building custom profiles and plugging them into the system, let's look at other issues that impact color management. Getting these issues squared away will make your custom profile more accurate.
Check Out Yourself, Your Environment, and Your Equipment
All the color profiling and monitor calibration on earth won't help you achieve color consistency across devices if you don't get your physical working conditions in order. Here are a few questions you should ask yourself:
Have you been to the eye doctor lately?
Are you taking cold medication? If so, it will really affect your color perception.
Have you cleaned the smudges off your eyeglasses? Your glasses aren't tinted, are they? Did you remember to park your sunglasses at the door?
Have you wiped the monitor screen clean lately? You aren't using a glare filter or one of those polarizing privacy screens, are you?
Is the monitor warmed up? Has it been on for at least 30 minutes before you use it for color work or before you create a new profile?
Do you work in a windowless room or one with heavily draped windows? You should, because the constantly changing qualities of natural light make it impossible to achieve accurate consistent color.
Is your artificial lighting even? No bare bulbs peeking out from under their shades? No hot spots reflected in the monitor, or shadows cast across it?
Is your lighting a neutral, subdued white? Or is the light in your workspace too blue because it is lit with fluorescent tubes, or too yellow because incandescent lamps provide your lighting. See whether you can get your boss to install professionally color-balanced lighting, or at least try to get the fluorescent tubes that profess to have fuller frequency ranges to mimic daylight. If you are using fluorescent bulbs, the next time they need replacing, change them to 5000K bulbs, available at most home improvement stores.
Are your walls, furniture, curtains, posters, paintings, and plants all a nice neutral, medium gray? Probably not. Be aware that light reflecting off everything in the room can change the color of the light in the room and alter your perception of the colors on your screen and the output from your printer.
Did you know that even the color of your clothing can make a difference? If your work is color critical, put on a light gray lab coat or artist's smock when you sit down to work. Who knows; your customers might be so impressed with your "technical" uniform that you could charge more. Or more likely, if you pay attention to everything on this list and in this chapter—your color work will be so dead on, your customers will beg to pay you more. Wouldn't that be nice (this is a rhetorical question)?
Have you extended the neutral gray color scheme to your desktop wallpaper, Windows title bars, and other screen elements? Let the color live in your work and not in your immediate surroundings.
Tip -Neutralize your desktop
Ideally, a 50% gray desktop would help you evaluate colors without influence. However, cursors tend to disappear at R:128, G:128, B:128.
Go a little lighter or darker with your desktop so it is still color-neutral, but you can make out your cursors.
We know you're eager to get to the fun stuff, creating something in Photoshop or ImageReady, and that you would like to finish all this hardware, techie stuff ASAP. But just as you have to do your exercises if you want to keep fit and trim, you have to put in some time now to get your system in shape so you can enjoy the good life of a successful Photoshop user.
Read Your Monitor Manual
Before you start to calibrate and create a profile for your monitor, using Adobe Gamma or any other calibration device, you need to find out on what color temperature your monitor bases its display. A monitor's temperature, also called its white point, is a value, measured in degrees Kelvin, that describes the point at which white light is produced from equal amounts of red, green, and blue light. Monitors are designed to operate at a white point that matches one of the standard illuminant temperatures defined by the CIE standards body. Some monitors offer a selection of operating temperatures from which the user can pick, while others offer only one fixed setting.
As you can see in Table 2.1, the default white point setting for Windows monitors is 6500 degrees Kelvin. This may be referred to as 6500K, D65, or daylight. The Macintosh OS default color temperature is 9300K (D93, or Cool White). The color temperature most often used in the publishing (to paper) community is 5000K (D50 or Warm White, Page White, or Paper White) because it produces a view that more closely resembles material printed on white paper. Other common white point settings are 5500K and 7500K. One of the latest trends among the CMS gurus is to use 6500K for both platforms.
Table 2.1 Default White Point Settings
Default White Point
Commonly Referred To As
Publishing to Paper
Warm White, Page White, or Paper White
Check your monitor's manual, its onscreen help, or the manufacturer's Web site to see whether your monitor offers a user-definable color temperature and how to make that selection. If your monitor does offer a choice of color temperature or white point, you should choose based on the work you do most often. If your work centers around print, use the monitor's controls to set the white point at 5000K. If you design mostly for Web or onscreen presentation, you could set your white point to the default temperature of the operating system used by most people who view your work. Or you could split the difference and set your hardware temperature to 7500K, if your monitor offers that choice (my monitor doesn't). Or you could set it to match the default setting for your operating system.
Older monitors may not offer user-definable color temperature, but you should still see what the fixed temperature of the monitor is. Whatever type of monitor you have, find out what the current white point setting is, change it if you can and want to, and then write it down. You will need this value handy when you use Adobe Gamma to calibrate and make an ICC profile for your monitor.
If you are unable to find any of this information, don't panic. Adobe Gamma has a measurement feature that will provide an approximate value for your monitor's white point.
Setting the color temperature and gamma when calibrating and profiling the monitor can be referred to as "setting the target." In work environments with more than one monitor, it is important always to use the same target when you're trying to achieve consistent color from one workstation to another.
This chapter is from Inside Photoshop CS, by Gary D. Bouton. (Sams, 2004, ISBN: 0672326442). Check it out at your favorite bookstore today. Buy this book now.