Printing
When you’re ready to print your image, use the following guidelines for best results:
Set the parameters for the halftone screen.
Print a color composite, often called a color comp. A color composite is a single print that combines the red, green, and blue channels of an RGB image (or the cyan, magenta, yellow, and black channels of a CMYK image). This indicates what the final printed image will look like.
Print separations to make sure the image separates correctly.
Print to film.
Printing a halftone
To specify the halftone screen when you print an image, you use the Screen option in the Print With Preview dialog box. The results of using a halftone screen appear only in the printed copy; you cannot see the halftone screen on-screen.
You use one halftone screen to print a grayscale image. You use four halftone screens (one for each process color) to print color separations. In this example, you’ll be adjusting the screen frequency and dot shape to produce a halftone screen for a grayscale image.
The screen frequency controls the density of dots on the screen. Since the dots are arranged in lines on the screen, the common measurement for screen frequency is lines per inch (lpi). The higher the screen frequency, the finer the image produced (depending on the line-screen capability of the printer). Magazines, for example, tend to use fine screens of 133 lpi and higher because they are usually printed on coated paper stock and on high-quality presses. Newspapers, which are usually printed on lower-quality paper stock, tend to use lower screen frequencies, such as 85 lpi.
The screen angle used to create halftones of grayscale images is generally 45°. For best results with color separations, select the Auto option in the Halftone Screens dialog box (choose Page Setup > Screens > Halftone Screens). You can also specify an angle for each of the color screens. Setting the screens at different angles ensures that the dots placed by the four screens blend to look like continuous color and do not produce moiré patterns.
Diamond-shaped dots are the most commonly used in halftone screens. In Adobe Photoshop, however, you can also choose round, elliptical, linear, square, and cross-shaped dots.
Note
By default, an image will use the halftone screen settings of the output device or of the software from which you output the image, such as a page-layout program. You usually don’t need to specify halftone screen settings in the following way unless you want to override the default settings.
1. | Make sure that the 18Start.eps image window is active. |
2. | |
3. | Choose File > Print With Preview, and make sure that the Show More Options check box is selected. |
4. | Immediately under the Show More Options check box, select Output from the pop-up menu.
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5. | Click Screen to open the Halftone Screen dialog box, and enter the following options:
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6. | Click Done to close the Print With Preview dialog box. |
7. | To print the image, choose File > Print. (If you don’t have a printer, skip this step.) |
8. | Choose File > Close, and don’t save your changes. |
 | For more information about printing halftones, see Photoshop 7.0 online help. |
Printing separations
By default, a CMYK image prints as a single document. To print the file as four separations, you need to select the Separations option in the Print With Preview dialog box. Otherwise, the CMYK image prints as a single, composite image.
In this optional part of the lesson, you can print the file as separations.
1. | Choose File > Open, and open the18Start.eps file in the Lessons/Lesson 18 folder on your hard drive. |
2. | |
3. | In the Print dialog box, make sure that the Show More Options check box is selected, and then set the following options:
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4. | Click Print. (If you don’t have a printer, skip this step.) |
5. | Choose File > Close, and don’t save the changes. |
This completes your introduction to producing color separations and printing using Adobe Photoshop.
 | For information about all color management and printing options, see Photoshop 7.0 online Help. |