Technical data
Color and Input/Output Options 99
Tips for Scanning
Scanning hardware and software varies considerably. One myth is that
the higher the resolution of your scanner, the better results you’ll
achieve. While that’s true in theory, the real limit to quality is how the
image will ultimately be reproduced. Will it end up on the printed page
or on-screen? Either way, the real issue is how many “extra pixels”
you’ll need in the original scan.
If the image will be professionally printed, will that be onto a sheet of
newsprint or a glossy coated stock? Paper itself puts a ceiling on
reproduction quality. Lower-grade paper tends to spread ink around
more easily, so the dots of ink used to print a picture need to be larger.
This means a wider halftone screen with fewer lines per inch (lpi).
If you’ll generate your output on a desktop printer, the device will be
putting bits of toner or droplets of ink on the paper. On a laser printer,
shades of gray result from variations in toner coverage. Desktop color
printers create color by laying down dots of cyan, magenta, yellow, and
black ink. Again, printer resolution and paper type are quite variable.
Dpi (dots per inch) is the most common measure of print quality.
♦ As a general rule, the optimal scanning resolution for print work (in
dpi) is about twice the output setting on the printer or other device
that will be used.
Or will your image end up on-screen instead of in print? If so, it will no
doubt be viewed at standard screen resolution of 96 dpi. (That’s why
this is the default resolution in PhotoPlus.) If you’re producing Web
images, it makes more sense to regard resolution as a fixed factor, and
think in terms of image dimensions instead.
This means that, for an image that will end up on a Web page, it’s just
possible you can get great results scanning at 100dpi, at exactly the
screen dimensions you need. But that’s cutting it close, especially if
you’ll be editing the image at all.
For either print or screen images, you must always take into account
what kinds of manipulations you plan to carry out on the image in your
photo editor, i.e. PhotoPlus. Color adjustments, resizing (with
resampling), blurring, and other effects tend to disturb the arrangement
of pixels in the original scanned image. So let’s add another guideline: