Graphics Programs Reference
In-Depth Information
Note
To determine the image resolution for a photograph you plan to
print, follow the computer-graphics rule of thumb for color or
grayscale images intended for print on large commercial printers:
Scan at a resolution 1.5 to 2 times the screen frequency used by
the printer. If the image will be printed using a screen frequency
of 133 lpi, scan the image at 200 ppi (133x1.5).
In computer graphics, there are different types of resolution:
The number of pixels per unit of length in an image is called the
image resolution
,
usually measured in pixels per inch (ppi). An image with a high resolution has
more pixels (and therefore a larger file size) than an image of the same dimensions
with a low resolution. Images in Photoshop can vary from high resolution (300 ppi
or higher) to low resolution (72 ppi or 96 ppi).
The number of pixels per unit of length on a monitor is the
monitor resolution
, also
usually measured in pixels per inch (ppi). Image pixels are translated directly into
monitor pixels. In Photoshop, if the image resolution is higher than the monitor
resolution, the image appears larger onscreen than its specified print dimensions.
For example, when you display a 1x1-inch, 144-ppi image on a 72-ppi monitor,
the image fills a 2x2-inch area of the screen.
