Although, apparently, Photoshop layers and the Shapes tools have nothing in common, when you get to real-world assignments, you'll find yourself continually using first one feature and then the other.
Why? Adobe has made creating shapes very simple, somewhat like opening a template of a design. To make image creation even easier, Adobe invented something called vector masks. Vector masks are pre-designed shapesthey act as tiny portals to layers underneath the layer upon which a vector mask resides, or they can appear as shapes against the background. You can change their color and add all sorts of wonderful effects to them. But...vector masksshapeswork only on layers, and that's why these two features are grouped into a single chapter.
Examining the Flexibility of Layers
Layers have been a Photoshop feature since version 3.0 (shortly after electricity was discovered). In passing years, Adobe has made the layers feature so powerful that today it almost overshadows Photoshop's most-used feature: the shipload of different ways you can select image areas.
In the sections that follow, you become familiar with Layer modes, layer locking, layer linking, clipping groups, clipping paths, layer sets, layer ordering, layer deleting, and Layer effects. Is learning all this stuff necessary? Yes, most certainly so; once you make layers a part of your Photoshop knowledge, you will work at least twice as fast as the next (uneducated) guy or gal.
First, we felt you'd benefit most from a potpourri-style tutorial, where you learn exactly what you need to know about a number of different layer tools and features. You'll see how efficiently you can work to perform complicated image editing.
Introducing the "Pocket Contents" Image
If someone were to ask you to empty the contents of your pockets on a table:
You're probably being booked for a crime, and
You'll notice that from an artistic standpoint, the composition formed by dumping your pockets is dimensional. Everything is not neatly ordered and distributed. This could be considered to constitute layers of things. Your keys might be above some folded money, and the folded money partially hides some pocket change.
The point here is that realistic image composition inherently has a depth of field; things go in front of and behind other elements. This is where Photoshop layers come in handy. They can help imitate real-world compositions.
Now, imagine you're Jim Carreythe only comedian whose adopted planet is Earth and you're asked to dump out your pockets on a table. The contents would probably be like the contents of the Pocket.psd image you'll work with in a moment.
The image looks like any other table top scene, except this scene was rendered in a modeling program, and everything is on different layers. FYI, shadows are attached to everything using the glow and shadow technique you will become familiar with in Chapter 5, "Working with Channels and Paths." Let's start off slow and easy as you learn how to manipulate the ordering of layers.
Investigating Layer Order
Open the Pocket.psd image from the Examples/Chap04 folder on the Companion CD, and save it to your hard disk using the same name and file type. This image is 600 by 800 pixels, with a resolution of 72 pixels per inch; zoom in or out if necessary to see all the contents of the image window.
Press F7 to display the Layers/Channels/Paths/And So On grouped palette.
Press V to switch tools to the Move tool.
And remember this shortcut: When the toolbox is partially hidden or closed, pressing V selects the Move tool directly, saving you the trouble of looking through the toolbox for the tool you need.
Right-click (Macintosh: hold Ctrl and click) over the 15ball in the image. As you can see in Figure 4.1, the context menu offers two layers presently underneath your cursor, called the 15ball and the Background. Click the 15ball choice, and you will see that the 15ball layer on the Layers palette is highlighted. You've made the 15ball layer the current editing layer.
Figure 4.1 Move directly to a layer you want to edit by right-clicking (Macintosh: hold Ctrl and click) the area you want to edit.
Avoid Auto Select Accidents When the Move tool is selected, the Options bar offers a checkbox for Auto Select Layer. We don't recommend using this option if you're a novice to Photoshopor even an intermediate user. When the option is checked, if you click anywhere in the image with the Move tool, you immediately move to the layer that was underneath your cursor. Can you see how this option can be both confusing and hazardous to your work?
You can take a safer route to select a layer quickly when the Move tool is active, however. Simply Ctrl()+click to move to a specific object on that layer. This enables you to change layers when it's convenient and avoids the accidental layer jumping you might do if Auto Select were enabled.
Drag the 15ball downward so that it is between the dart and the ice cream. Let's say we want the 15ball to play a more predominant role in the composition. No problem. On the Layers palette, drag the layer title for the 15ball up between the Soft Ice Cream layer and the Dart layer, as shown in Figure 4.2. This puts the 15ball layer between the dart and ice cream layers. And like me, you might not hit the "sweet spot" on the palette on your first try. If you release the layer title on top of a layer, it then resides directly beneath the layer upon which you dropped it. This technique might be worth a few practice stokes on your own.
Figure 4.2 Move the order in which layers are organized to place an object in front of another.
Moving Through Layers, the Fast Way We acknowledge that we are cramming your head with stuff here. If you feel you have the memory (the carbon-based, organic kind), you can learn a keyboard method to change a selected layer's position in the stack of layers. Press Ctrl()+] (right bracket) to move the chosen layer up by one layer. As you might expect, to demote a layer, press Ctrl()+[ (left bracket), one stroke per layer downward in the stack.
Photoshop uses the same ordering commands for layers as Illustrator and PageMaker do for objects.
Play around with the position of the 15ball as much as you like. There's no exam at the end of this chapter. It's sort of fun to see how the shadow and pool ball cover different layer items. Keep the image and Photoshop open.
A Photoshop layer has more than one property. A layer is not only a container in a stack of other layersit also can be changed with respect to opacity and how the layer's contents blend with layers underneath it. Come explore layer properties in the following section.
Changing the Appearance of a Layer
If you change a property of a layer in Photoshop, you also are likely to change the same property of whatever is on that layer. There are eight things that you can do to a layer, without mixing a layer with an additional, modifying layer (covered later in this chapter). The sections that follow introduce you to these different properties.
When you're using a selection tool or the Move tool, you can change the opacity of a layer and its contents by doing the following:
Planting your cursor in the Opacity field and typing. If you type a single digit, this represents 10 times the opacity applied. In other words, type 5, and 50% will appear in the number field. A zero (0) represents 100% opacity. Typing two numbers, one right after the otherno pausingwill enter these two numbers in the number entry field. Typing 5 and then 7, for example, will make the opacity 57%.
Typing a number value when your cursor is anywhere in the interface. This, too, affects the opacity of the current layer. This may not be your preferred method because it might be unsettling to type a number while working in a channel and inadvertently change the opacity of a layer.
Click the Soft Ice Cream layer title, click and hold on the palette's opacity flyout button, and then drag the opacity down to 57%, as shown in Figure 4.3. This is the direct, hands-on opacity determining method.
Figure 4.3 Create semi-transparent objects on a layer. Assign the layer partial opacity.
The Modes Drop-Down List
In Photoshop, you can paint using a certain mode you choose from the Options bar, and you also can put an entire layer's contents into most of the same modes. Photoshop has 22 modes, which means that you have 22 different ways to blend a layer into the underlying layers.
After using layer modes in several versions of Photoshop, I have discovered that there are four modes you'll use regularly: Normal, Multiply, Screen, and Overlay. You also will experiment on your own and find the perfect blending mode for your own images, but let's cover the "basic four" here and now:
Normal. Normal is the default mode, and the blend between the target layer and the layer(s) underneath is simple math. For example, if a layer is 50% opaque and the image underneath is 100% opaque, the resulting image at any point will be a color combination of 50% layer and 50% background image. Try making a bright blue background and a bright red layer, and then tuning the layer down to 50% opacity. The resulting color, in Normal mode, is a deep purple.
Multiply. This is a terrific blending mode for working shadows into images. Multiply mode replaces colors with a combination of layer colors that is subtractive in regions that are less than 50% in brightness. Huh? Okay, think of staining something light in color with a blue marker pen. Only the target area gets darker. Now, imagine a white marker. Writing across the surface of something with the white marker causes no difference in the surface's colordue to the fact that no subtractive color process is going on with a light color and a light target in Multiply mode.
Screen. If Multiply mode is like staining something, Screen mode is like bleaching something; it's the exact opposite effect. In Screen mode, lighter colors become more intense, while deeper colors do not change (and again, 50% brightness is the break point for what Photoshop considers light and dark). Try out Screen mode in the Pocket image, on the partially visible Ice Cream Cone layer. As you can see in Figure 4.4 (and much better on your own monitor), Screen mode really brings out the whites of the vanilla ice cream, and the deeper shadow areas on the cone seem to vanish.
Figure 4.4 Screen mode is useful if you have a layer with light colors that you want to separate off a dimly lit background.
Overlay. This mode produces an effect somewhat similar to placing a colored gel over an image. Overlay mode blends the image color with the Overlay color. Highlights and shadows do not change in brightness, but colors with a brightness between shadows and highlights are screened if they are over 50% in brightness. Additionally, colors are multiplied if the image's original color is less than 50% bright. You'll see a good example of this color mode in Chapter 5 with the ball and the pattern on the ball.
There are two more ways in which you can change the appearance of a layer, and both controls are located to the left of a layer title on the Layers palette.
The Fill slider on the Layers palette enables you to achieve two different kinds of opacity on a single layer. The Opacity setting controls the transparency of the layer; a setting of 100% means that the layer beneath the current layer cannot be seen through the objects on the selected later. A setting of 50%, however, fades the layer to allow 50% transparency so that objects on other layers will be visible through the current one. Fill (which is short for Fill Opacity) actually enables you to fade out the pixels or shapes you draw on the selected layer. It is used primarily when you have applied a layer effect, such as Emboss or Drop Shadow. When you reduce the Fill value, the pixels on the layer become increasingly transparent, but the layer effect remains.
Give the Fill control by trying this: Using the Pocket image (we're going to trash this image through the course of the chapter, so don't worry about messing it up), click the Soft Ice Cream layer, and with Opacity at 100%, drag the Fill slider down to about 50%. Ooooh, ghostly ice cream!
Now let's restore the Fill setting to 100% for this layer. We have more to do with this image, and you can always mess with the Fill feature (it's new to Photoshop 7, by the way) on other layered images later.
Visibility and Edibility Icons
The Layers palette shows two columns to the left of any layer. These columns contain icons that let you know which layers are visible and available for editing. The leftmost one concerns us here. Be patientwe'll get to the second one soon.
The visibility icon, in the leftmost column, is pretty self-explanatory. If there's an eye in the box, this means you can see the contents of the layer. If you click the eye, it disappears, and so does the visibility (and editing) of the layer's content.
Also, the Lock feature (new to version 7) has an option for painting. If you click the brush icon, you'll get one of those international "do not" symbols if you try to paint this layer.
Hide It and You Won't (Accidentally) Edit It Photoshop users have been leveraging the power of the visibility icon for years by turning the visibility of a layer off so that no accidental editing can happen to the layer.
The column to the left of the visibility column is called the Layer Link Mode column, and the appearance (or absence) of a link icon tells you whether a layer is linked. But you may actually see a few different icons in this column, depending on which state the layer is in. There are four possible states into which you can toss a layer: the target layer state, the Layer Mask state, the Layer Link mode, and the lock list. In the target layer state, the icon resembles a paintbrush; in layer mask, it looks like a gray rectangle with a white circle; and in layer link mode, the icon appears to be a chain. When you choose one of the lock list items, a small padlock appears to right of the layer name.
Target Layer State
You can paint on only one layer at a time in Photoshop, and you choose that layer by either keyboarding your way to a layer or by clicking its title on the Layers palette. When the layer is highlighted, it is called the target layer. A paintbrush icon in this column's box indicates that this layer is the target (current editing) layer. The title bar on the image also lists the current layer.
Layer Mask State
Later in this chapter, you edit the Pocket composition, using the layer mask. The quickest way to put a layer into the Layer Mask state is to choose the layer, and then click the icon that is second from the left on the bottom of the Layers palette. When a layer is in Layer Mask mode, you see the same icon in the box in the second column next to the Layer title.
What's this state do? Layer masks enable you to control the parts of the image you want to be able to edit, hide, or reveal. But not to worry! We're getting ahead of ourselves here, and you will play with the Layer Mask state later in this chapter!
Layer Link Mode
You'll be doing a step-by-step procedure with the Layer Link state later in this chapter, too. If you click in the second column box when the Paintbrush icon (target layer) isn't there, this layer turns into a linked layer, and a tiny chain appears in the column box. This layer is linked to the target layer, and if you use the Move tool to move the target layer's contents, the linked layer's contents moves correspondingly. This is a terrific feature when you have two objects aligned on different layers and you want to move them both, but you do not want to merge the layers. A click in a box that contains the link icon unlinks the layers.
We've saved the least critical three controls for layers for last. Don't worry if you find you are not using them daily in your work.
The Lock List
You've had a taste of this list with the Lock Image Pixels (that teeny brush icon). This horizontal list above the top layer title is probably used most often by intermediate to advanced users, primarily because these users are the ones who create intermediate to advanced problems in an image, and locking features are art-savers.
We have no tutorial to show you how the Lock choices work, so you might want to open a new image, and add a layer to it now. To do this, click the folded page icon directly to the left of the trash icon on the bottom of the Layers palette. Then use the Paintbrush tool to paint something, any color, on the layer.
The default setting for the layer Lock feature is Lock nothing. This means that no part of the layer is protected against accidental editing. You can paint over the first strokes you've made in the image window, and you also can paint over empty areas of the layer.
When you're ready to try out one of the Lock options, you can choose from Lock transparent pixels, Lock image pixels, Lock position, or Lock all. The paragraphs that follow explain each of these choices a bit more.
Set the Lock feature by clicking Lock transparent pixels, the first icon next to the word "Lock" (see item 1 in Figure 4.5). Enabling this feature locks the current opacity of the layer, no matter what the current setting might be. Any areas on that layer that have even 1% opacity (and it's doubtful any of us can see a 1% opaque area) cannot become more opaque, regardless of what tool you use to paint.
Figure 4.5 The Lock feature can disable painting over areas, prevent moving areas on a layer, and completely prevent editing on the target layer.
The next icon, Lock image pixels, shown as item 2 in Figure 4.5, keeps you from painting on the layer. Item 3, Lock position, stands for "no moving stuff, bud." With this icon selected, you cannot use the Move tool to accidentally or intentionally move any non-transparent areas on a target layer. Finally, item 4, Lock all, stands for "you cannot do anything to this layer; it is locked against everything."
You'll definitely use more options in your first months with Photoshop, but it's nice to see some of the most common ones and know what they do. Let's get back to our Pocket masterpiece, and explore more layer features.