Adobe Photoshop CS4 User Manual
Page 64
57
USING PHOTOSHOP CS4
Opening and importing images
Last updated 1/10/2010
Same image at 72-ppi and 300-ppi; inset zoom 200%
Unless an image is resampled (see “
” on page 59), the amount of image data remains constant as you
change either the pixel dimension or resolution. For example, if you change the resolution of a file, its width and height
change accordingly to maintain the same amount of image data.
In Photoshop, you can see the relationship between image size and resolution in the Image Size dialog box (choose
Image > Image Size). Deselect Resample Image, because you don’t want to change the amount of image data in your
photo. Then change width, height, or resolution. As you change one value, the other two values change accordingly.
Pixel dimensions equal document (output) size times resolution.
A. Original dimensions and resolution B. Decreasing the resolution without changing pixel dimensions (no resampling) C. Decreasing the
resolution at same document size decreases pixel dimensions (resampling).
A
B
C