Photoshop Fundamentals: Working wih Transparency
Adapted from The Non-Designer's Photoshop Book (Peachpit Press)
By Robin Williams and John Tollett
All layers, except Background layers, are transparent. Even if a layer is filled with pixels, such as an image, a fill color, or both, the layer itself retains transparency capabilities, allowing other layers below it to show through when pixels on the top layer are erased or masked.
You can give any layer a degree of transparency by adjusting its opacity. Whenever necessary, the Background layer can be converted from a non-transparent layer to a regular transparent layer.
Transparent layers are what provide the remarkable fexibility and creative potential of Photoshop—it’s important to understand how they’re working for you!
What is Transparency?
With the exception of “Background” layers (which are not transparent), image layers consist of opaque pixels against a transparent background. The transparent areas of a layer are represented by a gray and white checkerboard pattern. In the example below, the layer of Jimmy and Scarlett is above a layer that contains an image of flower blooms. Where the background of the top layer is erased (where you see the checkerboard), the flower bloom layer can show through. In addition, layer opacity can be adjusted to any degree of transparency, which opens up all sorts of visual effects possibilities.
Transparency PreferencesPhotoshop’s preferences allow you to decide how you want to be reminded that a layer is transparent, via a checkerboard grid (or not).
Lock the Transparent Pixels
When a layer contains both an image and areas of transparency, you can protect the transparent areas while you edit the image. For example, you might have an element on a layer, such as handlettering (shown below) that you want to add brush strokes to, without letting the brush strokes touch the background area. Locking the transparency enables you to do that. Photoshop refers to transparent areas as “transparent pixels,” so when we say “Lock transparent pixels,” we mean lock the transparency so that it’s protected and preserved.
Lock Image Pixels and Position
There are four “Lock” icons in the Layers panel; the first one is explained above. The other three Lock icons affect layer transparency in these ways:
When a layer is partially locked (when just one or two of the “Lock” items are selected), a white lock icon is shown on the layer (below-left).
When a layer is fully locked (when the “Lock All” icon is selected), a black lock icon is shown on the layer (below-right).
You can unlock the transparent pixels of a selected layer at any time in order to work in the transparent areas of the layer.
Use the Fill Setting for Special Effects
While the Opacity setting in the Layers panel determines how transparent everything on the layer is, the Fill setting, also in the Layers panel, affects only pixels, shapes, or text. It does not affect the opacity of layer effects that you’ve applied, such as drop shadows, bevel & emboss, stroke, etc.
Fill Image Pixels with Color
To color the image pixels on a transparent layer with the current Foreground color, without locking the transparency: Select the layer, then press Option Shift Delete (PC: Alt Shift Backspace).
To color the image pixels on a transparent background with the current Background color: Select the layer, then press Command Shift Delete (PC: Control Shift Backspace). This is similar to “Lock transparent pixels” mentioned above.
Change Background Layer Opacity
The opacity of a Background layer cannot be changed; you must convert the Background to a regular (transparent) layer. Do one of the following:
Save as TIFF with Transparency
You can save an image as a file that preserves its transparency to maximize design choices when it’s placed in a page layout application such as InDesign.
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|The Non-Designer's Photoshop Book by Robin Williams and John Tollett. Copyright © 2011. Used with permission of Pearson Education, Inc. and Peachpit Press.|