Graphics Programs Reference
In-Depth Information
2
Choose View > Actual pixels. The image may appear very large; you can pan the
image by holding down the spacebar and pushing the image around on the screen.
Position the image so that you can see an area with detail, such as one of the eyes.
Note that you should be in Actual Pixel view when using most i lters, or you may not
see accurate results on your screen.
Hold down the spacebar, and click and drag on the image area to adjust the position of the image
in the window.
3
Choose Filter > Convert for Smart Filters (this step is unnecessary if you already
converted your layers into a Smart Object). If an Adobe Photoshop dialog box appears
informing you that the layer is being converted into a Smart Object, press OK.
Smart Objects allow you to edit i lters more freely. Read more about Smart Objects
in Lesson 10, “Getting Smart in Photoshop.” An icon ( ) appears in the lower-right
corner of the layer thumbnail, indicating that this is now a Smart Object.
4
Choose Filter > Sharpen > Unsharp Mask. The Unsharp Mask dialog box appears.
You can click and drag inside the preview pane to change the part of the image that
appears there.
Unsharp masking defined
Unsharp masking is a traditional film compositing technique used to sharpen edges in an
image. The Unsharp Mask filter corrects blurring in the image, and it compensates for
blurring that occurs during the resampling and printing process. Applying the Unsharp Mask
filter is recommended whether your final destination is in print or online.
The Unsharp Mask filter assesses the brightness levels of adjacent pixels and increases their
relative contrast: it lightens the light pixels that are located next to darker pixels, as it darkens
those darker pixels. You set the extent and range of lightening and darkening that occurs,
using the sliders in the Unsharp Mask dialog box. When sharpening an image, it's important
to understand that the effects of the Unsharp Mask filter are far more pronounced on-screen
than they appear in high-resolution output, such as a printed piece.
In the Unsharp Mask dialog box, you have the following options:
Amount
determines how much the contrast of pixels is increased. Typically an amount
of 150 percent or more is applied, but this amount is very reliant on the subject matter.
Overdoing Unsharp Mask on a person's face can be rather harsh, so that value can be set
lower (150 percent) as compared to an image of a piece of equipment, where fine detail is
important (300 percent+).
Radius
determines the number of pixels surrounding the edge pixels that are affected by the
sharpening. For high-resolution images, a radius between 1 and 2 is recommended. If you are
creating oversized posters and billboards, you might try experimenting with larger values.
Threshold
determines how different the brightness values between two pixels must be before
they are considered edge pixels and thus are sharpened by the filter. To avoid introducing
unwanted noise into your image, a minimum Threshold setting of 10 is recommended.
