Unsharp Mask in Photoshop
Sharpening digital images is crucial step in getting your photos
ready for print, and can also greatly improve the quality of photos
for online presentation.
Most stock photography agencies, including TastyStock, do not
"pre-sharpen" their photos. This is left up to the designer,
as different situations call for different levels of digital sharpening.
"Unsharp Mask" is a filter found in Photoshop and other
graphic programs. In Photoshop, you can find Unsharp Mask in:
Filters > Sharpen > Unsharp Mask.
There are 3 settings under this filter:
Amount: defines how much sharpening is to be
applied to a photo...increasing this setting increases the contrast
along edges, making darker areas darker; lighter areas lighter.
An amount setting of 75-125 is a good starting point to begin
experimentation.
Radius: is the size of the area around pixels
that will be affected. Increase this setting as resolution/file
size increases. So, for screen resolution (online presentation)
a radius of around .5 usually works. For most photos headed for
the printer, a radius of 1.2 - 1.5 is recommended. For photos
without much detail, increasing this setting to around 3 can improve
upon the photo greatly.
Threshold: defines how much of the photographs
data/detail will be used to apply change. At 0, the filter will
affect everything...at higher settings the less detailed the sharpening
will be. A threshold of 3-4 is a good starting point.
For portraits, an increased setting of around 6 would be best
(if you don't want those pores and pimples being sharpened for
you viewing pleasure.)
So, settings of
125 - 1.5 - 3 (for print)
100 - .5 - 3 (for web/screen)
are basic starting points to start tweaking from.
Important Notes:
When sharpening for print, the on-screen preview of the photo
will usually look over-sharpened; even though when printed the
amount seems just right. Tests-runs, experience over time, and
talking to your printer will help you make sharpening decisions
for print.
Things to remember:
The Unsharp Mask is not for fixing blurry images,
only to bring out detail in an already focused image.
Sharpening should the last, or one of last edits you perform on
your image.
Be careful when sharpening photographs with flesh, over-sharpened
skin can look icky.
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