Identifying Color Issues

It used to be that importing color from graphics files into publishing programs was an iffy proposition ‚ colors would often not print properly even though they appeared correct on-screen. Those nightmares are largely a thing of the past, as modern page-layout software like InDesign can accurately detect color definitions in your source graphics, and modern illustration and image-editing programs are better at making that information accessible to programs like InDesign. So just note the following advice to ensure smooth color import.

If you create color images in an illustration or image-editing program, make sure that you create them using the CMYK color model or using a named spot color. If you use CMYK, the color is, in effect, pre-separated. With InDesign, any spot colors defined in an EPS file are automatically added to the Swatches pane for your document and set as a spot color.

Cross-Reference ‚

See Chapter 8 for more on creating and editing colors.

If your program follows Adobe's EPS specifications (Adobe Illustrator, CorelDraw, and Macromedia FreeHand all do), InDesign will color-separate your EPS file, no matter whether it uses process or spot colors. Canvas automatically converts Pantone spot colors to process colors in your choice of RGB and CMYK models. For other programs, create your colors in the CMYK model to be sure they will print as color separations from InDesign.

Color systems

There are several color systems, or models, in use, and InDesign supports the common ones, including CMYK (process), RGB, Pantone, Focoltone, Dainippon Ink & Chemical (DIC), Toyo, Trumatch, and Web. A color system defines either a set of individual colors that have specially mixed inks (shown on swatchbooks, which have small samples of each color) or a range of colors that can be created by combining a limited number of inks (such as RGB ‚ for red, green, and blue ‚ and CMYK ‚ for cyan, magenta , yellow, and black).

Chapter 8 describes the various color models, but for file import, it's best to use just three ‚ CMYK (process), RGB, and the Pantone Matching System ‚ since they're universally used and tend to be the most reliable when passing information from one system to another.

Note ‚

The advice on color systems applies to just vector images, since bitmap programs use CMYK or RGB as their actual color models, even if they offer swatchbooks of other models' colors.

Tip ‚

Most layout artists use Pantone to specify desired colors, so keep a Pantone swatchbook handy to see which CMYK values equal the desired Pantone color. (One of the available Pantone swatchbooks ‚ The Pantone Process Color Imaging Guide CMYK Edition ‚ shows each Pantone color next to the CMYK color build used to simulate it.) This book's companion Web site ( www.INDDcentral.com ) provides links to Pantone and other color swatchbooks.

Of course, you can simply pick a Pantone color from the electronic swatchbook in InDesign, and InDesign will convert it to CMYK if you specify it to be a process color (the default setting). Many high-end illustration programs, including Adobe Illustrator, support Pantone and can do this instant conversion as well. If available (as it is in InDesign), use the Pantone Process Coated color model because that is designed for output using CMYK printing presses. But remember: What you see on-screen won't match what you get on paper, so it's a good idea to have the printed Pantone swatchbook.

Calibrated color

With InDesign's Color Management System (CMS) feature enabled, the program will calibrate the output colors (whether printed to a color printer or color-separated for traditional printing) based on the source device and the target output device in an attempt to ensure that what you see on-screen comes close to what you'll see on the printed page. Although color calibration is a tricky science that rarely results in exact color latches across all input and output devices, it can help minimize differences as the image travels along the creation and production path .

Today, most image editing programs let you apply color profiles that conform with the International Color Committee (ICC) standards. If you're using color calibration, it's best to apply these ICC profiles in the images when you create them.

If you can't ‚ or forget to ‚ apply an ICC profile when creating your image, don't worry. You can add a profile (if you're creating images in a program that doesn't support ICC profiles) or apply a different one from InDesign.

Cross-Reference ‚

Chapter 29 covers color calibration in depth.