Photoshop
Layers
Layers Panel
We will examine what layers are and what the advantages are in using layers. You'll be introduced to the Layers panel and its functions by completing a practice exercise.
What is a Layer?
A layer allows multiple elements in a Photoshop image to interact with each other in different ways while remaining separate entities. If you were to take three overhead transparencies and stack them on top of each other, you would see, in essence, how a layer works. Let's say one contains some black title text and the other two contain coloured pie charts. The colours of the pie charts would change when one is overlaid onto another. If the title text was on the top layer, it would block out the pie charts underneath. Where all three transparencies have common areas containing no ink, you could see right through them. You could change the order of the transparencies and write on one with a marker to see how they visually change. This is essentially how Photoshop's layers work. A layer's power is in the fact that it can be manipulated in various ways to change how it interacts with other layers while still remaining independent.
What Can Layers Do?
Photoshop layers give you the ability to manipulate an image without making changes to the original image data, combine various images or elements into one composite image, apply blending or styles to elements, or mask out portions of an image.
Examining the Layers Panel
The Layers panel is where the majority of your work with layers will take place. Let's examine it in detail. If it's not already open in your workspace, go to Window > Layers.
Creating a New Layer
To create a new layer, click on the New Layer button at the bottom of the Layers panel. The icon looks like a small pad of paper with the top sheet folded up.
A new layer will be displayed in the panel with a default name, such as Layer 2.
Duplicating a Layer
Layers can be duplicated by dragging them to the New Layer button at the bottom of the Layers panel and releasing the mouse button.
Creating a Layer Group
Photoshop allows you to create a folder in which a number of layers can be stored. This is called a layer group. Certain image manipulations, when applied to the group, will affect all layers in the group. However, these layers will still interact with the other layers outside the group. To create a layer group, click once on the New Layer Group button at the bottom of the Layers panel. A new layer group will appear in your layer list with a name like Group 1. You can then drag and drop the layers you want into that group. Make sure that you drag the layer over the layer group name and it is highlighted before releasing the mouse button.
Once a layer group is created and you have added layers to the group, you can collapse the folder in the Layers panel to hide all the layers in the group to keep things compact and tidy. Image manipulations that can be applied to an entire layer group include:
- masks
- blending modes, and
- repositioning the group within the image.
Nested Groups
Additionally, you can create layer groups within other layer groups if you need to. Keep in mind that some older versions of Photoshop that don't support nested groups, or even any groups for that matter, will still display the grouped layers, but not the groups themselves. The layers will be taken out of the groups. Photoshop 6 and 7 support groups (called "sets" prior to CS2), but not nested groups. Photoshop versions prior to 6 do not support any kind of grouped layers.
Changing Layer Stacking Order
A layer's position in the stacking order can be changed, moving it up or down in the layer list. To do this, simply click and drag the layer to the position you wish. The Layer > Arrange submenu contains the commands: Bring to Front, Bring Forward, Send Backward, Send to Back. These can also be used for moving layers within the stacking order.
Deleting a Layer
You can delete a layer by clicking and dragging the layer to the bottom of the panel and releasing the mouse button on top of the Delete Layer button. It has an icon that looks like a trash can.
Showing or Hiding Layers
Layers can be shown or hidden by clicking once on the icon to the left of the Layers panel that looks like an eye. This can be useful for viewing the image without certain elements, especially those that might be obscuring your view of something on underlying layers. When the eye icon is displayed, the layer is visible, When the eye icon is not displayed beside a layer, that layer is hidden. If there are multiple, contiguous layers you want to show or hide, you can drag the pointer through the Show/Hide column instead of clicking on each layer individually.
Linking Layers
A link can be created between multiple layers so that the positions of the elements do not change in relation to each other. This means that you can still move the linked layers around, but each element in the multiple layers will act and move as though they were on one layer.
To establish a link between multiple layers, Shift-click to select contiguous layers, or Ctrl-click (Cmd-click) to select non-contiguous layers. Each selected layer will be highlighted in blue. The layers can be temporarily manipulated in this way, but if you select any other layer (without Shift or Ctrl) they will become deselected. To establish a more persistent link between the layers, click the Link Layers button 
at the bottom left of the Layers panel. Each linked layer will display the link icon to show that it is linked.
Unlinking Layers
To unlink layers, simply reverse the process you used to link them. Select the layers and click the Link Layers button again. You can also remove a layer from the linked ones by selecting just that layer, and once again clicking the Link Layers button.
Locking Layers
Different layer attributes can be locked to avoid unwanted erasing or movement. In the Layers panel there are four options for controlling the locking of elements in a layer. Enabling one of the check boxes locks that particular attribute.
Lock Transparency: This will lock all transparent pixels on a layer. When in effect, you can't apply any changes to transparent pixels.
Lock Image Pixels: This will lock all transparent and opaque pixels on a layer. When in effect, you can't make any editing changes to the layer.
Lock Position: This will prevent you from moving the content on a layer.
Lock All: This will lock the transparent and opaque pixels and the layer position.
Changing Layer Opacity
The opacity (or transparency) of a layer can be changed to allow underlying layer elements to show through. To change the layer opacity, click on the button to the right of the Opacity value to display the slider control. Drag the triangle on the slider to set a value. You can also double-click on the Opacity value and type a new value. 100% represents a layer with no transparency, and 10% represents a layer with a high level of transparency.
Changing Layer Fill Opacity
While the layer Opacity affects the opacity of everything on the layer, the Fill opacity affect pixels, shapes and type but doesn't apply to layer styles like drop shadows and strokes.
To illustrate the difference between Opacity and Fill, look at the image shown here. The circle is a layer shape with a stroke layer style applied to it. Each circle is on its own layer.
- Opacity: 100%, Fill: 100%. Everything on the layer is at full opacity.
- Opacity: 30%, Fill: 100%. Notice that both the fill and the stroke are semi-transparent.
- Opacity: 100%, Fill: 0%. The fill is completely transparent and the stroke is fully opaque.
Practice Exercise: Working with Layers
Let's try out the various options in the Layers panel so you can get the feel of it. We'll intersperse the instructions with new material as we go along.
- Open a new document that is 300 px by 300 px and set the Background Contents to white. Name it layers_practice.psd.
Background Layer
Your Layers panel should look like this. Every new image where you specify the Background Contents as white or a background colour opens with one layer named Background. The contents of this layer can't be repositioned nor can the Background layer be moved to another position in the layer stacking order when more layers are present. You'll notice that the Blending Mode, Lock and Opacity controls are greyed out so they can't be used on a Background layer. The padlock icon to the right of the layer name confirms that this layer is locked in all aspects apart from the fact that you can edit the pixels.
Note: Alternatively, you can promote a Background layer to a normal layer and then you can access the full set of layer features.
Active Layer
The Background layer is highlighted in blue. This means that it's the active layer. Normally, only one layer at a time can be edited (such as by painting). However, as you'll see later in the course, it's possible to apply transformations to a group of linked or selected layers all at one time. Also, some of the painting and editing tools have an option that will let you apply them to all layers.
-
Insert a new layer by clicking on the New Layer button at the bottom of the Layers panel. New layers are always placed above the active layer and, once added, they become the active layer. They are assigned generic names like "Layer 1", "Layer 2", etc. They can be renamed. (In fact, it's usually a good idea to rename your layers when you create them to avoid confusion later on, especially with a more complex file.)
-
Use the Elliptical Marquee tool to create a vertical oval selection on "Layer 1" and fill it with a colour. Remove the selection marquee by pressing Ctrl-D (Cmd-D).
- Insert another new layer.
-
Create a horizontal oval selection that overlaps the oval on "Layer 1". Fill it with a different colour and remove the selection. Your image should look something like this:
-
Your Layers panel should now look like this:
-
We'll add a new layer using menu commands this time. Go to Layer > New > Layer. The New Layer dialog will open where you can set options for your layer.
- Type "airbrush" in the Name field and select yellow from the Colour pop-up menu. Click OK to close the dialog.
-
A new layer has been added to your Layers panel named "airbrush" and the layer visibility column has been colour-coded in yellow.
-
Select the Brush tool 
and enable its Airbrush option 
. Set a new foreground colour and paint random strokes on the "airbrush" layer.
-
Click on "Layer 2" to make it the active layer. Click on the eye icon to hide the layer. The horizontal oval should disappear from your image document.
-
Try holding your pointer over the image document. You should see an icon
displayed that means you can't edit the layer. This is because hidden layers are unavailable for editing. This prevents you from accidentally editing a layer you can't see.
- Make "Layer 2" visible again by clicking in the layer visibility column for the layer. The eye icon should reappear.
-
Drag the airbrush layer down and drop it over the New Layer button. This will create a duplicate layer named "airbrush copy". The layer colour-coding was also duplicated.
-
Go to Layer > Duplicate Layer which will open the Duplicate Layer dialog.
-
Accept the default settings and click OK. The new layer was assigned the name "airbrush copy 2". Your layers list should look like this:
-
Hold down the Alt (Option) key and click on the New Group button in the Layers panel. The New Layer Group dialog will open. Accept the defaults and click OK. A new layer called "Group 1" is inserted at the top of the layers list.
Used by themselves, the New Layer and New Layer Group buttons will not open a dialog so you can set the name and layer colour-coding. However, pressing the Alt (Option) key while clicking on these buttons will generate the dialog. This is also true if you are duplicating layers or layer groups by dragging and dropping them on the panel buttons.
-
Drag "airbrush copy 2" over the "Group 1" name or folder icon and drop it. It should be indented a bit to the right underneath "Group 1". Do the same with "airbrush copy". With the airbrush layer, drag and drop it between the other two airbrush layer copies.
-
Your layer group should look like this:
-
Click on the inverted triangle to the left of the "Group 1" folder icon. All of the layers you added to the group will be hidden in the Layers panel but their content will still be visible in the image. The triangle will now be pointing to the right. Clicking on the triangle is how you expand and collapse layer groups.
Layer groups are a great way to organize your layer content. You can still edit and show/hide each individual layer in a group yet you can manipulate the group layer and all the layers in the group will be affected by the change. For example, if you hide the group layer by clicking in the layer visibility column, it will hide all the layers in the group. If you delete the group layer, all of the layers in the group will also be deleted.
-
Expand "Group 1" and remove one of the airbrush layers from the group by dragging it above the "Group 1" layer. Do the same with the other two airbrush layers. We're going to create a layer group a different way.
-
With one of the airbrush layers as the active layer, Ctrl-click (Cmd-click) on each of the other airbrush layers to select all three, then click the Link Layers button . A chain link icon should appear in all three layers. Now the layers are linked together.
-
Go to Layer > New > Group from Layers. The New Group from Layers dialog will open. Type "airbrush" in the Name field and click OK. All of the linked airbrush layers will be automatically added to the layer group.
-
Delete the now-empty "Group 1" layer by dragging it on top of the trashcan icon and releasing it. Layers can be deleted the same way. Using this method, you bypass the prompt dialog asking if you want to delete the layer or group. The alternate methods that will display the prompt are:
- Use the menu command: Layer > Delete Layer or Layer > Delete Group.
- Select Delete Layer or Delete Group from the Layers panel menu.
- Click on the Delete button in the Layers panel.
- Hide the "airbrush" layer group in your image by clicking in the layer visibility column.
-
Make "Layer 2" the active layer. Change the opacity of the layer to 50% by using the Opacity slider or by double-clicking in the Opacity field and typing "50". Your Layers panel and image should look like this:
- Drag "Layer 2" so it's below "Layer 1".
- Change the opacity of "Layer 1" to 75%.
-
Set a foreground colour that you haven't used yet. Click on the Lock Transparency check box 
to enable it. Select the Airbrush tool and sweep it around on "Layer 1". Paint will only affect the areas of the image that already contain pixels. The transparent areas will be unaffected when transparency is locked. Fill the rest of the oval by using the shortcut command Ctrl-Backspace (Cmd-Delete).
-
Unlock the transparency and enable Lock Image Pixels.
-
Choose a light foreground colour and try painting on "Layer 1". Result: You can't. The icon that indicates you can't edit will be displayed. This prevents you from using painting tools on the layer.
-
Disable Lock Image Pixels. You haven't learned the Move tool officially yet but let's try it anyway. Select the Move tool in the Toolbox.
- Click and drag it in the image. The oval on "Layer 1" should move around. Use the Undo command to restore the oval.
-
Enable the Lock Position check box 
and try to move the oval again. You'll see a message saying, "Could not complete your request because the layer is locked." A grey padlock icon will appear to the right of the layer name, just like the Background layer.
-
Disable Lock Position and try the last lock option: Lock All. 
A black padlock icon will appear on the layer and the Blending Mode menu, Opacity, Fill, and the other Lock options will be greyed out. This is called a fully locked layer. The only change that can be made to it is a change in stacking order. You won't even be able to delete it when it's fully locked.
-
Click on the "airbrush" layer group. Enable its visibility.
-
Enable Lock All and expand the group so you can see the layers in the group. All of those are locked as well but their locks are dimmed. None of their properties can be edited.
- Disable the locking on the layer group and "Layer 1".
-
Double-click on the Background layer. The New Layer dialog will appear. Click OK. The layer is now called "Layer 0". You've just promoted the Background layer into a regular layer and it can be edited like any other layer. The menu command is Layer > New > Layer From Background.
-
Your layer will look like this:
-
To convert any layer to a Background layer, go to Layer > New > Background From Layer. Try this with "Layer 0".
-
Make "Layer 1" the active layer. Use the Rectangular Marquee tool to select a portion of the oval.
-
Go to Layer > New > Layer via Copy or use the keyboard shortcut Ctrl-J (Cmd-J). Hide "Layer 1" so you can see the new "Layer 3" fully. Pixels from the selected area were copied and placed on a new layer above the source layer. The source layer was unaffected.
-
Your Layers panel should now look like this:
-
You can also cut pixels from a layer to create a new layer. On "Layer 3", use the Rectangular Marquee tool to select some of the pixels. Go to Layer > New > Layer via Cut or use the keyboard shortcut Shift-Ctrl-J (Shift-Cmd-J). Hide "Layer 4" (the newest layer) to see that the pixels from the selection were removed from "Layer 3".
- Select "Layer 3" and "Layer 4" and delete them by dragging them both to the Delete Layer button. Re-display the "airbrush" layer group and "Layer 1" and save your file.
This has been a lengthy exercise but it's important to feel comfortable working with layers if you want to get the most benefit and flexibility out of working in Photoshop. Much of what you practiced here will be used repeatedly throughout the course. There are a few options we skipped over that will be introduced in subsequent lectures.
Layers Panel Summary
- Layer contents remain as separate entities and can be manipulated independently of each other unless layer groups are used. Then certain transformations can be applied to the entire group at once.
- A Background layer is locked for all but editing with the painting tools. A Background layer can be converted into a regular layer and vice versa.
- New layers can be created by inserting new, empty layers, by duplicating existing layers, or by promoting selections to a separate layer.
- To set options when creating new layers or new layer groups, use the menu commands or hold down the Alt (Option) key while clicking on the New Layer button or New Layer Group button. To set options when duplicating layers or layer groups, use the menu commands or hold down the Alt (Option) key while dragging a layer onto the New Layer button or New Layer Group button.
- Normally, only one layer at a time can be edited and that is the active layer.
- Clicking and dragging a layer in the layers list will change its position in the stacking order. Layers can be removed from or added to layer groups in the same way.
- The content on linked layers can be repositioned as one unit but for every other editing change, the layer content remains as separate elements.
- Changing layer opacity allows objects on layers below to show through.
- The visibility of layers can be toggled by clicking in the Show/Hide column. Hidden layers cannot be edited.
- Layer groups can be collapsed or expanded by clicking on the triangle on the group layer. Hiding the group layer will hide all layers in the group.
- When Lock Transparency is enabled, the transparent pixels on the layer cannot have paint applied to them.
- When Lock Image Pixels is enabled, none of the painting tools can be used on the layer.
- When Lock Position is enabled, you can't use the Move tool to reposition the layer contents.
- When Lock All is enabled, no editing can take place except for a change in the layer stacking order.
- Partially locked layers will display a grey padlock icon. Fully locked layers (Lock All enabled) will display a black padlock icon.
Layers Panel Keyboard Shortcuts:
- New Layer with options: Alt (Option) + click New Layer button
- New Layer Group with options: Alt (Option) + click New Layer Group button
- Duplicate Layer with options: Alt (Option) + drag layer to New Layer button
- Duplicate Layer Group with options: Alt (Option) + drag layer to New Layer Group button
- New Layer via Copy: Ctrl-J (Cmd-J)
- New Layer via Cut: Shift-Ctrl-J (Shift-Cmd-J)
- Select contiguous layers: Shift-click
- Select non-contiguous layers: Ctrl-click (Cmd-click)
Photoshop - TOC - Introduction - Books -
Layers - Links - Questions -
[ 1 ] - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - A - B - C - D -
