Layers have been a feature of Adobe Photoshop since version 3 of the program came out in 1995. This feature has been refined over the iterations of the program to include Adjustment Layers, Layer Masks, Vector Shape Layers, Text Layers and even Layer Styles. This now indispensable feature has even made it into the consumer version of the application, Photoshop Elements. For those of us who started with Photoshop before there were layers, and have seen these features added gradually with each new version it has been a fairly manageable learning curve. For newer users this can be a dizzying miasma of concepts and jargon that easily intimidates. This month, we’ll try to sift through the layers and see if we can unearth the basic concepts behind this very useful tool.
First we should talk about exactly what a layer is. If it helps, think of each layer as a sheet of clear tracing paper over the base background image. Things that you do to one layer don’t necessarily affect other layers or the background. This opens up a world of possibilities for manipulating separate parts of a composition. Some of this selective adjustment of your images can be accomplished with Photoshop’s selection tools, but layers lend you additional flexibility. The Layers palette is your control center for selecting and working with layers, while the Layers menu gives you access to extra commands and functionality.
There are several ways that you can create a new layer. The easiest is to make a selection and then Copy and Paste it on top of another image. You can also use the Move tool to drag one image onto another window to generate a new layer. Some tools and functions in Photoshop automatically create a new layer by default, the Text or Shape tools for example. You can also click the New Layer icon on the Layers palette or select New Layer from the Layers menu.
palette shows the layers of the file stacked in order (Fig. 1
). The one at the top of the list will be visible ‘above’ the ones below it. To the left of each layer is an eyeball icon, clicking this toggles that layer’s visibility. The box next to it indicates whether you are working on the layer or it’s mask and let’s you link one layer to another. At the top of the palette is the Blending Mode
pop-up, by default set to Normal
basically just shows the one image over the other, other modes will composite the two images in a variety of different ways including lightening or darkening the underlying image. Next to this is the Opacity
slider. This changes how much of the underlying image is seen through this layer, 100% means the layer is opaque, 0% makes the layer completely transparent. The lower the number, the fainter the layer appears. This is useful if you want to subtly ghost one image over another.
Below that is an area that is labeled Lock. Clicking any of these icons will lock various aspects of the layer: transparent pixels, the pixel fill colors, positioning or all of these. Left of that in Photoshop, but not Elements, is the Fill slider. This is similar to the Opacity slider, except that it does not change the opacity of Layer Styles. Again, very cool effects can be achieved with this function.
At the bottom of the Layers palette is a row of icons. From left to right they are Layer Style, Layer Mask, New Layer Set, New Adjustment Layer, New Layer and Delete Layer. Photoshop Elements skips a few of these as well. These functions are also available in the Layers palette menu (the triangle at the top right of the palette) or in the Layers menu.
Having an element in your composition on it’s own layer allows you to move the layer around at will or put disparate pieces together (Fig. 2
). You use the Move
tool or the arrow keys to move the layer around. Any painting, scaling, rotating or other manipulations to that layer will not affect the image below. The Layer Styles
let you add common effects like drop shadows (Fig. 3
), glows and textures. When you add a Layer Style
you will see an icon on that layer with a drop down triangle and a list of the Layer Styles
below. Double-clicking the icon or the Layer Style
listing will allow you to edit the settings. Layer Styles
are available in Photoshop Elements
only through the Layer Styles
palette. There you will find many cool predefined effects, the settings are editable, but less so than in the full version of Photoshop
A very important thing to remember when you are working with layers is that there are only a few file formats that will preserve the layers. Photoshop’s native PSD file format is the best choice (Fig. 4). Photoshop CS, 7 and Elements 2 will let you save layered TIFF or Photoshop PDF files. Few programs take advantage of this new aspect of the TIFF specification. Many older programs will be confused or overtaxed by layered TIFF files so there is no compelling reason to use it. A layered Photoshop PDF is useful if you want to do further work with the file in Adobe Acrobat Professional to add animation or interactivity, but most users should stick to the PSD format.