Adjustment Layers

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Adjustment Layers

An adjustment layer differs significantly from a raster layer. Instead of adding pixels to your image, an adjustment layer seems to modify the brightness, contrast, or color of pixels on lower layers. The word "seems" is important here. No pixels on lower layers are actually changed; it only appears that they are. This is a crucial distinction, because it means that adjustment layers enable you to fine-tune your adjustment at any time, even in a later editing session (provided you save your image in PSPimage format or in another format that supports layers).

Adding an Adjustment Layer

There are nine available adjustment layers: Brightness/Contrast, Channel Mixer, Color Balance, Curves, Hue/Saturation/Lightness, Invert, Levels, Posterize, and Threshold. Each of these is entirely equivalent to the corresponding adjustment available in the Adjust menu.

To add an adjustment layer, choose L ayers > New Ad j ustment Layer and choose the adjustment that you want. Once you've chosen a particular adjustment, the Adjustment tab of the adjustment layer's dialog box is displayed (except in the case of Invert, which has no controls). When you're finished choosing whatever settings you want, click the OK button to return to your image and apply the adjustment.

Editing an Adjustment Layer

An adjustment layer is a greyscale bitmap. When the active layer is an adjustment layer, the only colors available in the Material palette are 256 shades of grey (including black and white). The shade of grey painted on an adjustment layer determines to what extent the adjustment is applied to lower layers beneath the painted area. You edit an adjustment layer by painting it with black, white, or shades of grey (black removing the effect from certain areas, grey lessening the effect, and white for the full effect). However, you can't see the data on an adjustment layer, only the effects on lower layers.

There is a way to see an adjustment layer's data, though. To get a representation of the adjustment layer's data, click the layer's Overlay button in the Layer palette. By default, a red overlay is displayed that is 50 percent opaque in areas that are completely affected, is completely transparent where the effect is not applied, and has lowered opacity elsewhere. When you want to turn the overlay off completely, just click the Overlay button again.

NOTE

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Sometimes this overlay makes it hard to see the image, and in that case you can change the color and opacity of the overlay on the Overlay tab of the adjustment layer's property dialog box.

Whenever you want to change the settings of an adjustment layer, call up its property dialog box. Do this just as you would for a raster layer: Double-click the layer's layer button, right-click the layer button, and choose Properties, or choose L ayers > P roperties from the menu bar.

Limiting the Effects of an Adjustment Layer

By default, an adjustment layer affects an entire layer unless you paint away areas of the layer. However, you can also limit the effects of an adjustment layer to certain areas of a layer by making a selection before adding the adjustment layer. For example, Figure 4.40 shows the effect of adding a Posterize adjustment layer with no selection, while Figure 4.41 shows the effect with a rectangular border selected.

Figure 4.40. An adjustment layer affecting an entire layer.

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Figure 4.41. An adjustment layer affecting only a selected area of the layer.

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Once you've added the adjustment layer, you can turn the selection off.

Also by default, an adjustment layer affects all layers that are lower in the layer stack. You can limit the effect of the adjustment layer to a single layer or set of layers by creating a layer group and adding the adjustment layer and the layer or set of layers to the group. Figure 4.42 shows an image with an Invert adjustment layer above two raster layers, the lower one containing a pattern and the higher one containing some beveled text. Figure 4.43 shows the same image with the adjustment layer and text layer grouped together, with the pattern layer outside the group .

Figure 4.42. An image containing an adjustment layer and two raster layers.

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Figure 4.43. The same image with the adjustment layer grouped with only one of the raster layers.

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Paint Shop Pro 8 Power
Paint Shop Pro 8 Power!
ISBN: B001QCXEI6
EAN: N/A
Year: 2006
Pages: 125
Authors: Lori J. Davis

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