Tutorials

Aim for the color management bullseye

By Olav Martin Kvern and David Blatner

When you aim at a target—and it doesn’t matter whether you’re aiming a rifle, a bow, a laser, or a camera—you have to make adjustments. You’ve got to consider the atmospheric conditions, the distance to the target, the characteristics of the target itself. Once you know what the variables are, and how they affect what you’re trying to do, you’ve got a better chance of hitting the bullseye.

The same thing is true in color management. You need to understand the tools you have to work with, how they work together (or don’t), and how they combine to produce the colors you see in the printed version of your publication.

It would be nice if we could make what we see on our screen exactly match what we’ll get when we print. But we can’t, for a variety of practical and physiological reasons (not to mention simple lack of time and money). That said, we must also add that we can get very close—and we can also make the relationship between the display and the printed piece more consistent and predictable.

The “device” (a printer, scanner, monitor, or printing press) is the key. Every device renders colors in a slightly different way. To adjust color in one environment so that it matches the color as seen in another environment, color management systems refer to a file containing information on the color characteristics of a device (how it displays or prints color). This file is called a “device profile.”

Device profiles for scanners and printers are usually created by the manufacturers who make the hardware, though quite a few come with Adobe® InDesign® CS2. You’ve got to make monitor profiles yourself, because every monitor is different (just as several television sets from the same manufacturer can show the same image differently). The process of creating a device profile is called “characterizing” a device.

Once a device profile has been created for a device, you’ve got to maintain (or “calibrate”) the device so that it doesn’t vary from the profile. Imagesetter operators and commercial printers calibrate their equipment regularly (or should) to match industry standards.

The InDesign color management system uses device profiles compatible with the International Color Consortium (ICC) specification. If you’re on the Macintosh, you can also use device profiles provided by Apple with the system-level ColorSync color management system (these profiles are also ICC compatible).

Get more information

Color management is an enormous subject and we can only focus on one aspect of the big picture here: How color management works in InDesign. If any terminology is confusing to you (like gamut, ICC profile, color engines, and rendering intents), we encourage you to go look at two other sources for a truly in-depth look at getting consistent color. First, because most of what you want to manage is probably created in Adobe Photoshop®, check out a book that David wrote with Bruce Fraser: Real World Photoshop. Then, to really see how all this fits together, see Real World Color Management, by Bruce Fraser, Chris Murphy, and Fred Bunting

Do you need color management?

Everyone wants consistent color from original to screen to proof print to printing press, but it’s worth asking yourself whether you really need it. Managing color is not as simple as turning on a checkbox, and though it’s not as hard as flying an airplane, it can still cause a fair amount of rifling through medicine cabinets trying to ease the pain in your head. You may not need to worry a lot about managing color in InDesign if you can rely on color swatch books when picking solid colors, and if you can rely on color prepress professionals to deal with your color Photoshop images.

There are other instances when it’s not even worth trying to get InDesign to manage your color. For example, InDesign can’t manage grayscale images or spot colors (unless you convert them to process colors). Similarly, InDesign isn’t really set up to color-manage vector art when saved as an EPS file (it can do it, but we don’t recommend it). Vector art saved as PDF or native Adobe Illustrator® (.ai) files should work reasonably well.

Nevertheless, we must admit that it is particularly satisfying when you work through all the issues and achieve (as close as possible) parity among your screen, inkjet printer, and final press output. Being able to rely on your screen (“soft proofing”) and desktop color printer is a great boost in efficiency, too. Plus, as the world becomes increasingly reliant on direct to plate technologies, bypassing film entirely, color management systems become increasingly important to ensure quality output. And if you want to import RGB images and let InDesign do the color separation for you at print time, you’ll get better results if color management is turned on.

Controlling your color-viewing environment

If it’s important to you that what you see on your screen looks as much like the printed version of your publication as possible, there are a few rules you need to follow:

• Use a monitor and video system capable of displaying at least 24-bit color.
• Characterize and calibrate your monitor with a tool like Gretag-Macbeth’s EyeOne device. If color is of critical importance to you and your publications, find a system that works with your monitor, or buy a monitor that works with the calibration system you prefer.
• Control the lighting around your monitor and keep it consistent when you’re working. Just about everyone agrees that the fluorescent lighting used in most of our office buildings is the worst possible lighting for viewing colors. Turn it off, if you can, and rely on incandescent lighting (desk lamps with one sort of bulb or another) to light your work area. If you can’t turn it off, try getting some “full spectrum” (or “amber”) fluorescent tubes to install above your monitor. These also reduce eyestrain.
• Control the lighting of the area where you’ll be viewing your color proofs. Ideally, you’d have a room or small booth equipped with “daylight” (or 5,000-degree Kelvin) lamps—but few of us can afford the money or space required.

Why is lighting important? Basically, the temperature of the light affects what a color “objectively” looks like. You can’t assume ideal viewing conditions, but you have to work in them to be able to do consistent work

Is what you see anything like what you’ll get?

One of the simplest rules for getting the color you expect is also one of the least technologically advanced: Any time you’re working with ink, refer to printed samples, rather than looking at the colors on your screen. Remember that, unlike the paper you’ll be printing on, your screen is backlit, so it displays colors very differently from what they’ll look like when printed.

If you’re using uncoated paper, look at samples of the ink (spot color) or ink mix (process color) printed on uncoated stock. If you’re using coated paper, look at examples printed on coated paper. If you’re using a colored paper, try to find an example of the ink printed on a colored paper—though these examples are much harder to find (if it’s a big enough job, your printer might be willing to make a “draw down” for you by mixing the ink and scraping it on the paper by hand).

Pantone makes a line of swatch books showing their libraries of spot and process colors (including process color equivalents of the spot colors); they’re printed on both coated and uncoated stocks, and, although they’re kind of expensive, they’re not as expensive as pulling a job off of a press because you didn’t like the press check. They’re downright cheap if you consider what they must cost to print.

However, we don’t recommend you use Pantone spot colors (the ones you find in the Pantone spot color library) to specify a process color. The Pantone Matching System is a spot-color specifying system, and the colors don’t convert to process colors particularly well because you can’t make any given hue just using process colors (see the discussion earlier in this chapter). While Pantone also makes a swatch book with a spectrum full of process colors, we tend to like the one made by Trumatch even more; it’s just easier to use for some reason.

Don’t assume that color printers will automatically produce an accurate simulation of what the colors in your publication are going to look like when they’re printed by your commercial printer. To do that, you’ll have to do some work—you’ll have to run test pages and adjust device profiles. And, at the same time, bear in mind that most color printers print using something akin to the process-color method. Your spot colors will be converted to process colors during printing. Some of the six- and seven-color inkjet printers can produce good matches for most spot inks.

Note, however, that the color proofs you print on a color inkjet printer cannot show you the way that your pages will print on a printing press. In particular, they can’t show you trapping problems. For that, you need to use one of the color proofing processes (such as Chromalin or Press Match) to create your proofs from the film you’ve gotten out of your imagesetter. Imagesetting service bureaus frequently offer color proofing as part of their business. Some of these proofing processes can give you a proof on the paper you’re intending to use, or can give you transparent overlays that you can place on top of your selected paper to get an idea of what your publication will look like when printed. If you’re printing direct to plate or direct to press, then there won’t be any film from which to burn proofs and you have to be all the more careful when setting up your files.