In the last hour we covered moving objects to the front and to the back. We learned that each object was on its own level. Continuing on the topic of levels, it's time to learn about the king of all levels in Illustrator: layers. If you've worked in Photoshop, you're probably familiar with the concept of layers. If you'll forgive me for using the analogy, layers are similar to mechanical overlays. Clear sheets of acetate, these each contain parts of artwork, and when they are laid over each other, they form the complete art. Layers are extremely versatile and can really help keep complex illustrations under control and manageable. By viewing only certain layers, you can concentrate more easily on the task at hand. In this chapter, we learn all about these layers, including:
Illustrator's layers are specified in the Layers palette. When you start a document, all artwork is automatically placed on a layer (see Figure 5.1). To open the Layers palette, choose Show Layers from the Window menu (see Figure 5.2).
Illustrator's Layers palette.
Choosing Show Layers from the Window menu.
There's a small controversy between designers as to when to create layers. Some artists prefer to create several layers before they begin working, adding the art to each layer as they progress. Others prefer to add or delete layers as necessary, as they work on a project. Still others like to create the entire piece, and then chop it up into different layers. No matter which way you do it, though, you have to learn how to add and discard layers.
The easiest way to create a new layer is to click the New Layer button at the bottom of the Layers palette (see Figure 5.3). Illustrator creates the layer and assigns it a name. Don't worry, you won't have to keep your layers named "Layer 1" and "Layer 2." We'll change that when we learn about layer options later this hour.
The New Layer button.
Another way to create a new layer is to select New Layer from the Layers palette menu (see Figure 5.4).
Choosing New Layer from the Layers palette menu.
To delete a layer, click the name of a layer and drag it to the Trash icon in the lower-right corner of the Layers palette (see Figure 5.5). Alternatively, you can delete a layer via the Layers palette menu. But what if the layer you are deleting contains artwork? Turns out Illustrator is keeping a watchful eye out for us. If you try to delete a layer with art on it, you get a warning message alerting you about the situation, and Illustrator only proceeds to delete the layer and its contents if you click OK. Otherwise Illustrator returns you to the document with the layer intact, where you can copy the art to another layer (see "Moving/Copying Items Between Layers" later in this hour).
Deleting a layer with the Layers palette Trash icon.
Sometimes you want to make a copy of an entire layer. You can easily create a duplicate of a layer by clicking the name of an existing layer and dragging it to the New Layer icon on the bottom of the Layers palette (see Figure 5.6). Again, you can also create a duplicate by selecting Duplicate Layer from the Layers palette menu. The attributes, as well as all the artwork contained on that layer, are duplicated, and Illustrator adds the word "copy" to the layer name.
Creating a duplicate layer by dragging an existing layer on top of the New Layer icon.
Each layer has several attributes that facilitate your work, as well as add functionality to the layers. Double-clicking the name of a layer brings up the Layer Options dialog box (see Figure 5.7). Here you can name the layer, which is an important step. As you add more and more layers, it becomes increasingly difficult to remember which items are on Layer 23 and Layer 14. By giving intuitive names to layers (such as "Template," "Wheels," or "Ad Copy"), you can quickly identify where items are. In the Layer Options dialog box, you can also assign a selection color (see "Layer Colors," later in this hour), and choose to show, preview, or lock the layer (these are also discussed later in this chapter).
Double-clicking the name of a layer brings up the Layer Options dialog box.
There are two more options found in the Layer Options dialog box: Print and Dim Images. By unchecking the Print box, you are telling Illustrator that you do not want the objects in this layer to print. You might want to create a layer where you write notes to yourself or a colleague, and putting it on a non-printing layer assures the text won't print when you send it to a client or for film separations. There also might be times when you have a complex illustration but only want to print specific parts of it.
Time Saver: In today's fast-paced world, a designer is sometimes forced to send a fax of a design to a client for instant approval. Fancy backgrounds and tints, however, can make text very difficult--if not impossible--to read when faxed. If you create your text and backgrounds on separate layers, you can use Layer Options to print only the text layer so that your client can read the clear text without the background. Just remember to set the background layer to print again before you send for final output.
The Dim Images button is used for when you want to use placed images as a template. Upon placing a bitmapped image, Illustrator dims the image to make it easier to trace over it. Try to avoid using this feature if possible, as it slows screen redraw. Of course, if you have no other choice, remember to turn the option off when you are done tracing. For more details on tracing images, see Hour 21, "Working Smart in Illustrator."
If you have one or two layers in your document, it's pretty simple to keep track of which objects are on which layer. But in a document with many layers, it becomes increasingly difficult to remember which objects are on each layer. To make it easier to identify which object is on which layer, a color is defined for each layer. When an object is selected, it is highlighted in the color of its layer. When you create a new layer, Illustrator automatically assigns a new unique color to that layer. To change the color of a layer, simply double-click the layer to bring up the Layer Options dialog box, choose a new color (see Figure 5.8), and click OK.
Choosing a new layer color.
What good would layers be if you couldn't shuffle the order of them around? By simply pressing and dragging on the layer name, you can change the order of the layers (see Figure 5.9). The order of layers determines which objects are in front of others. The objects of a layer closer to the top of the list in the Layers palette appear on top of those objects in layers closer to the bottom of the list.
You can change the order of layers by simply dragging them.
Many times you need to move objects from one layer to another. Instead of making you copy and paste objects, Illustrator has an intuitive feature built in to the Layers palette specifically for the purpose of moving and copying objects between layers.
When an object is selected, notice a little dot on the far right of the layer name in the Layers palette (see Figure 5.10). To move your selected object to another layer, simply click and drag the dot to another layer (see Figure 5.11), and the object is transferred to the new layer. The selection color changes to the new layer's color, too.
The little dot on the far right indicates your selection.
Dragging the dot to a different layer.
To copy objects to another layer, press and hold the (Option)[Alt] key as you drag the dot. A copy of your selection is put into the new layer.
One of the advantages of using layers is the ability to quickly lock or hide the objects on each layer. Notice that to the left of each layer are two boxes (see Figure 5.12). The left-hand box controls the view, whereas the right-hand box controls locking. An eye in the left box indicates that the layer is fully visible in your document.
The visibility and lock boxes are on the far left of the Layers palette.
To hide the layer, click the eye, and the objects in that layer aren't visible in your document. Clicking again in the left box makes the layer visible. If you press and hold down the (Command)[Control] key while you click in the left-hand box, you set the layer to Artwork mode, as opposed to Preview mode. The little eye icon is hollow, indicating the change (see Figure 5.13). Simply (Command-click)[Control-click] again to return the layer to Preview mode.
A hollow eye in the visibility box indicates the layer is in the Artwork view mode.
Click in the right-hand box and a pencil with a line through it appears indicating that the layer is locked (see Figure 5.14). Objects in a locked layer are visible in your document, but cannot be selected. To unlock the layer, click again in the right-hand box.
In this document, layers Parking Garage, Cheap Hotel Rooms, and Health Spa are locked. Hotel Suites, Offices, and Restaurants are hidden, and Parking Garage, Security, and the Lobby layers are in Artwork mode.
It's important to remember that regardless of whether a layer is visible or locked, it prints unless you specify it as a non-printing layer in the Layer Options dialog box.
Layers are an important part of Illustrator, and we covered that in depth today. Although you may not use layers for simple illustrations, they can really come in handy as your illustrations become more complex. Speaking of complex, the next chapter introduces you to the most difficult part about Illustrator: the Pen tool and the Bézier curve--the heart of Illustrator.
Layer color--Refers to the selection color of items on that layer (that is, if an object is selected, its anchor points appear in the color of that object's layer color).
Layer order--The stacking of layers upon each other. The layer order is determined by the position of each layer in the stack.
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