Adobe 13102498 - Photoshop CS3 - Mac User Manual page 73

Change the print dimensions and resolution
When creating an image for print media, it's useful to specify image size in terms of the printed dimensions and the
image resolution. These two measurements, referred to as the document size, determine the total pixel count and
therefore the file size of the image; document size also determines the base size at which an image is placed into
another application. You can further manipulate the scale of the printed image using the Print command; however,
changes you make using the Print command affect only the printed image, not the document size of the image file.
If you turn on resampling for the image, you can change print dimensions and resolution independently (and change
the total number of pixels in the image). If you turn off resampling, you can change either the dimensions or the
resolution—Photoshop adjusts the other value automatically to preserve the total pixel count. For the highest print
quality, it's generally best to change the dimensions and resolution first, without resampling. Then resample only as
necessary.
Choose Image > Image Size.
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2 Change the print dimensions, image resolution, or both:
• To change only the print dimensions or only the resolution and adjust the total number of pixels in the image
proportionately, select Resample Image and then choose an interpolation method.
• To change the print dimensions and resolution without changing the total number of pixels in the image, deselect
Resample Image.
To maintain the current ratio of image width to image height, select Constrain Proportions. This option automat-
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ically changes the width as you change the height, and vice versa.
4 Under Document Size, enter new values for the height and width. If desired, choose a new unit of measurement.
Note that for Width, the Columns option uses the width and gutter sizes specified in the Units & Rulers preferences.
For Resolution, enter a new value. If desired, choose a new unit of measurement.
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To restore the initial values displayed in the Image Size dialog box, hold down Alt (Windows) or Option (Mac OS),
and click Reset.
See also
"Position and scale images" on page 486
"Print images" on page 484
"Specify columns for an image" on page 42
"Selecting halftone screen attributes" on page 493
Determine a suggested resolution for an image
If you plan to print your image using a halftone screen, the range of suitable image resolutions depends on the screen
frequency of your output device. Photoshop can determine a recommended image resolution based on the screen
frequency of your output device.
Note: If your image resolution is more than 2.5 times the screen ruling, an alert message appears when you try to print
the image. This means that the image resolution is higher than necessary for the printer. Save a copy of the file, and then
reduce the resolution.
1 Choose Image > Image Size.
Click Auto.
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PHOTOSHOP CS3 66
User Guide