|
Scanning Guidelines
Determine the output
size and resolution
Resolution
and image size are issues that most novice scanners overlook.
In order to get the best scan possible you need to know 2 variables
before scanning.
- The
physical size of the scanned image. Commonly measured in
inches, centimeters, etc.
- The
resolution of the image, correctly expressed as
Pixels
Per Inch or PPI. Note: this is not the same thing
as DPI or Dots Per Inch but is often incorrectly
labeled as such. DPI is a printing function — how many
dot per inch your printer is capable of printing…Without
making this any more confusing than it already is here’s
some guidelines:
Web output
72 PPI
Digital
presentation output 100 PPI
Wide-format
poster output 100 PPI
PowerPoint
35mm slide output 150 PPI
Publication/Journal
output 300 PPI
Dye Sublimation
printer 300 PPI
Set
size and resolution
Scanner
interfaces allow you to set your size and resolution requirements.
It’s important to note that scanned images are bitmap in
nature and not vector based. Once an image is scanned changing
the size or resolution results in a reduction in quality. Information
must be discarded or interpolated to create a new image size.
Adjust
the preview marquee to crop the image
Fine tune
the cropping using the marquee to select how you want the image
to be scanned.
Scan
the image
Hit the
button!
Sharpen
the image
Use Unsharp
mask in Photoshop to sharpen your scanned image. Find this in
Photoshop under Filter, Sharpen, Unsharp Mask.
There are many variables that affect what the settings should
be, try experimenting and use the preview window to see the results
of changing the amounts. Use the values shown as a starting point.
Adjust
color and density
Many color
management issues affect how you adjust your scan. Important consideration—just
what is your monitor doing??
Suggestions:
If
you’re scanning for web, bring up a web browser and
adjust to match.
If you’re
scanning for slide output have one imaged and adjust your
monitor to
match the slide. The same procedure can be applied to printer
output.
Using the
variations feature in Photoshop is a great basic way to adjust
the color and density of an image. This can be found under Image,
Adjust, Variations. There are more advanced methods
for tonal adjustment that can be found in the Image, Adjust
menu selection. Try exploring the Levels and Color Balance
options.
Variations
offers a visual ring around with color and density.
Remove
any defects
 Use
the Clone tool in Photoshop to remove dust and scratches. It copies
an area that the user defines and "Paints" that information
where specified. You can control the size of the brush to customize
the area of correction. To select a copy from area select this
tool and hold down the option key and click. Then move to the
area that requires the correction and click to apply.
Save
the image
TIFF,
PICT, and JPEG are very common digital file formats.
If you’re importing your file into Powerpoint use PICT and
avoid compression. For Web scans use JPEG and choose your level
of compression carefully. More compression will save you space
but will reduce image quality. For publications the most commonly
requested format is TIFF. All three will go from Mac to PC, check
your specific application for the recommended file type.
|
