Adobe 13102498 - Photoshop CS3 - Mac User Manual page 70

PHOTOSHOP CS3 63
User Guide
About monitor resolution
Your monitor's resolution is described in pixel dimensions. For example, if your monitor resolution and your photo's
pixel dimensions are the same size, the photo will fill the screen when viewed at 100%. How large an image appears
on-screen depends on a combination of factors—the pixel dimensions of the image, the monitor size, and the
monitor resolution setting. In Photoshop, you can change the image magnification on-screen, so you can easily work
with images of any pixel dimensions.
20"
15"
832 x 624 / 640 x 480 1024 x 768 / 640 x 480
A 620- by 400-pixel image displayed on monitors of various sizes and resolutions.
When preparing images for viewing on-screen, you should consider the lowest monitor resolution that your photo
is likely to be viewed on.
About printer resolution
Printer resolution is measured in ink dots per inch, also known as dpi. Generally, the more dots per inch, the finer
the printed output you'll get. Most inkjet printers have a resolution of approximately 720 to 2880 dpi. (Technically,
inkjet printers produce a microscopic spray of ink, not actual dots like imagesetters or laser printers.)
Printer resolution is different from, but related to image resolution. To print a high quality photo on an inkjet printer,
an image resolution of at least 220 ppi should provide good results.
See also
"About desktop printing" on page 483
"Preparing images for press" on page 491
Screen frequency and printer resolution
Screen frequency is the number of printer dots or halftone cells per inch used to print grayscale images or color
separations. Also known as screen ruling or line screen, screen frequency is measured in lines per inch (lpi)—or lines
of cells per inch in a halftone screen. The higher the resolution of the output device, the finer (higher) a screen ruling
you can use.
The relationship between image resolution and screen frequency determines the quality of detail in the printed
image. To produce a halftone image of the highest quality, you generally use an image resolution that is from 1.5 to
at most 2 times the screen frequency. But with some images and output devices, a lower resolution can produce good
results. To determine your printer's screen frequency, check your printer documentation or consult your service
provider.
Note: Some imagesetters and 600-dpi laser printers use screening technologies other than halftoning. If you are printing
an image on a nonhalftone printer, consult your service provider or your printer documentation for the recommended
image resolutions.