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Tuesday, October 4, 2011

Layers & Creative Sharpening

Gain more control with sharpening layers


This Article Features Photo Zoom
1a) Sharpening Layer Blend mode set to Normal
1b) Sharpening Layer Blend mode set to Luminosity



In the September/October issue of DPP, we discussed creative sharpening
with the Unsharp Mask (USM). In this issue, we're going to examine how to use layers to gain finer control over the USM when you're using it creatively. There are many ways to modify sharpening effects using layers.


2a) Blend If sliders used to reduce clipping highlights and shadows
To get started, create a sharpening layer by duplicating the background layer and renaming it.

Layers can be used to eliminate saturation shifts. Change the Blend Mode of a sharpening layer from Normal to Luminosity. Color noise will be reduced this way. Layers can be used to prevent clipping in deep shadow detail (near-black) and bright highlight detail (near-white). As sharpening is a contrast effect, near-white and near-black values can be driven to pure white and pure black by it. There's a cure. Double-click the layer to activate Layer Styles. Use the Blend If sliders to reveal the lost highlight and shadow detail in the background layer below the sharpening layer; zoom way into a highlight area, hold the Option/Alt key and drag the right arrow to restore highlights and the left arrow to restore shadows.

Layers can be masked for greater control over confined areas in an image. To begin, add a layer mask. Select an area from which you wish to remove a sharpening effect, like a sky or other area of even tone, and fill the area with black. You can use this strategy to remove unwanted texture or noise from selected areas of an image. Gray values can be created on a mask with the Gradient tool or with a Brush tool to gradually reduce a sharpening effect. This often can produce a more strongly felt impression of space within an image. In anticipation of selectively modifying an effect, you may decide to sharpen an image more aggressively.


2b) Before Blend If sliders used
2c) After Blend If sliders used
One approach to gaining additional flexibility with sharpening effects is to set a sharpening layer to 50% Opacity before applying the filter and then later adjust the opacity up or down to get more or less of the effect. This can be useful, but be mindful of its limitations. Reducing or increasing a sharpening layer's opacity will provide an effect similar to adjusting Amount; more or less contrast is added. But modifying opacity can't simulate the effects of different Radius settings—thicker or thinner contours.

If you choose to apply USM as a Smart Filter, you'll be able to reset the filter's settings quickly and easily in current or future editing sessions, but you won't be able to use the Blend If sliders to reclaim delicate highlight and shadow detail.

You can quickly make note of the settings you've applied on a layer by taking a screenshot. With the USM dialog open, on a PC, press Print Screen and then paste the screenshot from the clipboard; on a Mac, hold Shift/Command 4, press the space bar and click, then open the screenshot on your desktop and drag the layer into your layered Photoshop document. So that this layer doesn't remain visible, turn it off or clip it to the sharpened layer; it's only a note used for possible future reference.

For creative sharpening, evaluate the effects of the USM filter when viewing images at a screen magnification of 100%.


3) Sharpening layer with sky masked
You can get a faster preview and a better before-and-after comparison by selecting a portion of an image with the Marquee tool before applying USM. This can be especially useful for large files. It usually enlarges the area of the preview of the effect and gives you a simultaneous before (outside) and after (inside) comparison. For best results, select an area that contains a variety of textures within an image. As you don't want to apply the filter inside the selected area only, you can choose either to remember the settings you've determined, deselect and then apply the filter at those settings to the entire image, or apply the filter, undo the filter (Command/Control Z), deselect (Command/Control D) and reapply the filter (Command/Control F).

Reduce noise before sharpening. Sharpening routines often accentuate noise, sometimes adversely. If the effects generated by USM routines are adverse, consider creating an edge mask to constrain the effects to contours only. Or, use an alternate sharpening routine—high-pass sharpening.

Both topics will be covered in future articles.

John Paul Caponigro, author of Adobe Photoshop Master Class and the DVD series R/Evolution, is an internationally renowned fine artist, a lecturer and workshop leader. Get over 100 lessons with his free enews Insights at www.johnpaulcaponigro.com.

 

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