| There are three settings for Imagener's Unsharp Mask
function. If you look at the main Imagener screen, the Unsharp
Mask function is the section that we renamed "Resharp." In
this section, Amount is the first value
on the screen (reading down), then Radius and Threshold.
Amount refers to the intensity of
the Unsharp Mask or "Resharp" effect. A setting between
100% and 200% will do, depending on the Radius. The bigger
the Radius, the less Amount needed. My "standard" Amount
setting is 120% however, some images need more than this, and
others less.
Radius refers to the dimension,
in width, of every sample that will be affected by the Unsharp
Mask algorithm - a piece of a program that has a specific function.
Choose a setting between 1 and 1.5, depending on the image
resolution of the file (see our March
2005 newsletter for more information about Image
Resolution), and designate for the Amount (above) and resolution
of the file. The higher the resolution of the image, the greater
the setting should be for the Radius value. The formula that
we recommend is: Output resolution divided by 200. This can
change depending on the image content. Complex images will
optimize with different settings than images with simpler content.
For example, designate a Radius of 1 for a 200 dpi (dots per
inch) image. Designate a radius of 1.5 for a 300 dpi image.
The more Amount you use, the less Radius is necessary.
Threshold specifies how many numbers
of samples in an image will be sharpened. A setting of 0 will
affect every sample, whereas a setting of 50 will affect almost
none of the samples. Highly detailed images such as line art
require a setting of 3, whereas portraits look best with a
setting of 5 to 9 (try to keep minor wrinkles down to a minimum).
It can take a while to come up with the right combination
of settings for an image. That's why many photo software programs
offer some form of sharpening as an option during image capture,
and most commonly this functionality is the industry standard "Unsharp
Mask" functionality that is also included in Kneson Software's
Imagener product line.
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