Mastering Photoshop CC Layers

1

Layer Foundations

Layers are one of the most, if not the most important tools in Photoshop. Without layers, many of the advanced editing techniques like compositing, Blending Mode effects and Masking just wouldn’t be possible. This first chapter provides you with an introduction to the basics of layers in Photoshop. This is to ensure you have the required level of understanding to benefit from the rest of the book. Even if you feel you already have this, please don’t be tempted to skip ahead. You could miss important information that you might not realise you don’t know.

What are Layers?

Probably the best way to understand layers and how Photoshop uses them, is by looking at an example image containing layers.

Figure 1 - Image with layers in the Photoshop Layers Window

Here we can see an image of a man walking along a pier at sunset. The scene didn’t happen as you see it here. The man didn’t walk on the pier at sunset but earlier in the day. This is a composite photo where different elements are combined or created from different photos.

To the right of the image, you can also see a screenshot of the Photoshop Layers Window. The Layers Window displays the different layers present in the open image, although not all image types will support layers. The JPEG format is an example of an image format that doesn’t support layers whilst TIFF and the Photoshop PSD both support layers. For this reason, when you open a JPEG file, there is only ever one layer.

In the screenshot here, you can see there is the Background layer at the bottom. This is the default layer when you open an unmodified image. Above this are two other layers which in this example are called Man and Shadow. The shape of the man was cut out from a second photograph taken earlier in the day and then added to this image as a separate layer.

The man’s shadow was then created using a second copy of the man, on another layer. Whilst it’s a little more advanced, you can see how the shadow was created in this YouTube video (https://youtu.be/W9n6N7YOgpc).

Let’s now look at a short exercise to help better understand how layers work and explore some of their features.

Exercise 1.1 – Layer Basics

For this exercise, please use the supporting image Understanding Layers.psd which is included in the accompanying image files for the book. If you haven’t done so already, you can download this from my Lenscraft website on the Downloads for Books page. The following is a direct link to the page (https://lenscraft.co.uk/learn-photo-editing-books/useful-downloads-books/). You will find links to download the supporting files for all my books on this page.

Open the Understanding Layers.psd file in Photoshop. You should see in the Photoshop Layers Window that it contains the three layers mentioned above (Background, Man, Shadow). If you can’t see the Layers Window, it may be hidden. You can toggle its visibility on and off using the Photoshop menu Window | Layers….

Figure 2 - Elements of the Photoshop Layers Window

In the Layers Window you will see there is a small eye icon to the left of each layer (number 1). This controls the visibility of the layer. Clicking it will toggle the visibility of the layer off and on. Try clicking the Shadow layer eye icon once to hide the shadow. Next hide the man and then finally the Background layer.

After hiding the Background layer, you should see the image area turn to a grey and white checkerboard pattern. This shows the transparent areas of the image and is called the canvas. If you click to toggle the visibility of the Man layer on again, you will see it only covers part of the checkerboard pattern, but the rest remains transparent. This is because there are only pixels on the layer where the man appears. When he was cut from another image, he was placed onto a transparent background.

Now turn on the Background layer. This completely covers the transparent area of the image canvas, but it doesn’t cover the man. That’s because the layer with the man sits above the Background layer in the Layers Window. The bottom layer is Background and the layer above it is the Man layer. When we have layers stacked up like this, we call it the Layer Stack (number 2). The position of each layer within the Layer Stack is important and contributes to the effect it produces in the image. The image preview you see in the main area of Photoshop is the combination of the visible layers in the Layers Window or Layer Stack. It’s possible to reorder the layer to create a different result.

Earlier we said the Background image is a layer, but that isn’t entirely correct. There are some things that you can’t do with the Background layer until you convert it to a regular layer. For example, you can reorder layers in the Layer Stack by clicking and dragging them with your mouse. But if you try to click and drag the Background Layer to move it you will find you can’t.

To convert the Background layer to a regular Layer, click the small padlock icon (number 3) which you will see at the right side of the layer in the Layers Window. Alternatively, you can double click on the Background layer thumbnail in the Layers Window, or select Layer | New | Layer from Background… in the Photoshop menu. Choose whichever method you feel comfortable using.

After converting the Background image to a Layer, you will see its name in the Layers Window change to Layer 0. You will find you can now click and drag Layer 0 to reposition it above the Man layer in the Layer Stack. As you move the layer into position, you will see the new position becomes highlighted in blue. You can then release the mouse button to drop the layer into position.

When you position Layer 0 above the Man layer in the Layer Stack, the man will vanish. This is because the pixels of the man are now covered by the pixels of Layer 0.

One way to show the man again without repositioning the layer is to reduce the Opacity of Layer 0. To do this, click on Layer 0 in the Layers Window to select it. Then at the top of the Layer Window you will see the Opacity control (number 4) which is set to 100%. Click the control and reduce the slider to 50%. This causes the pixels in Layer 0 to become semi-transparent. You will then see the man through the transparent image. As you will see later, reducing the Opacity of some layers can be a great way to control the strength of their effect.

Unfortunately, with pixel layers like in this image, the result doesn’t look convincing. Return the Layer 0 Opacity setting to 100% and then reposition the layer at the bottom of the Layer Stack. You can also turn on the visibility of the Shadow layer so that all three layers are visible in the image again.

Click the Man layer in the Layers Window to select it. Look to the top of the Layers Window and to the left of the Opacity slider. There you will see a dropdown showing Normal (number 5). This dropdown is called the Blend or Blending Mode and is something we can set for each layer in the image. This controls how the pixels of the man blend with the pixels in the layer or layers below it in the Layer Stack. When set to Normal, the pixels of one layer will cover and hide the pixels in the layers below it.

Next, click the Shadow layer in the Layers Window to select it. If you check the Opacity of the layer, you will see that it’s set to 86%. This allows the boards of the pier to show through the pixels, helping to create the shadow effect. If you reduce the Opacity, it makes the shadow lighter but if you increase the Opacity, it becomes darker.

Whilst we can control the strength of the shadow using the Opacity slider, it’s not the only control being used. Notice at the top of the Layers Window the Blending Mode is set to Multiply rather than Normal. This causes the pixels of the Shadow layer to blend with those of the lower layers, allowing us to see through the layer. Change the Blending Mode in the dropdown to Color Burn and you will see the shadow darken. Change it again to Darken and the shadow is a little lighter.

Each of the Blending Modes uses a different method of blending the pixels of that layer with the layers below it, but all are based on mathematical calculations. In a later chapter of the book, we will look in depth at the different blending modes and explore some ways you might use them in your editing. For now, return the Shadow layer to the Multiply setting.

At this point we’ll end the exercise. You should now understand that layers can be used to build up the overall image. In the example we looked at, the image was created from three different layers, each of which contained a component of the image.

Common Layer Types

Now it’s time to expand our understanding of image layers by looking at some of the different layer types.

So far, we have only considered pixel-based layers. These are layers that are filled (or partially filled) with pixels. One characteristic of this type of layers is that when the pixel layer is placed above another in the Layer Stack, the pixels will cover the lower layers, hiding them. There are three ways to avoid this happening:

Use a Layer Mask attached to the upper layer. This then hides the pixels allowing the lower layers to be seen. You will find an introduction to layer masks later in the book.

Reduce the Opacity of the upper layer. This increases the transparency of that layer, allowing any lower layers to show through.

Apply a Blending Mode to the upper layer. This controls how it blends with the layers below it. We will be looking at Blending Modes in depth later in the book.

This point is important. When working with layers, their order will affect the results and when a pixel layer covers other layers, it can produce unexpected results. You may find yourself scratching your head at times, wondering why an adjustment doesn’t seem to be working. If you find yourself in this position, check the effect of the pixel layers in the image by turning them off and on using the eye icon in the Layers Window.

The second type of layer to consider is an Adjustment Layer and there are several types. We will be looking in detail at the different Adjustment Layers in Photoshop in a later chapter.

Adjustment Layers don’t have content like pixel-based layers, but instead adjust the content of layers below them. They do this by applying mathematical calculations that can change the colour and/or tone (how light or dark something is) of the image pixels. Fortunately, you don’t need to understand any maths to be able to use them.

One big difference between an Adjustment Layer and a Pixel Layer is that an Adjustment Layer won’t cover or hide the layers below it. In this way, it’s possible to build up different adjustments using multiple Adjustment Layers. Each layer then acts on the layer or layers below it.

Sometimes you may find that you only want an Adjustment Layer to affect one of the layers in the Layer Stack. You can achieve this by creating something called a Clipping Mask. This restricts the effect of the Adjustment Layer to the layer that it’s clipped to.

Let’s look at an exercise to demonstrate how this works.

Exercise 1.2 – Adjustment Layers

For this exercise, please use the support image file Understanding Layers.psd. This is the same file that we used in the previous exercise. If you made any adjustments to the image in that exercise, close the file, without saving it, to start again.

With the image open in Photoshop, click the Shadow layer (1) in the Layers Window to select it. You can then click the Add new adjustment layer icon (2) at the bottom of the Layers Window.

Figure 3 - Adding an Adjustment Layer to the image

When you click the Add new adjustment layer icon, Photoshop displays a list of available Adjustment Layers you can select. In the list, click the Levels Adjustment Layer. You will then see the new Levels layer appear in the Layers Window, above the layer that was selected.

If you select the Levels layer in the Layers Window by clicking it, you will see it’s controls in the Properties Window. If you can’t see your Properties Window open in Photoshop, check the Windows menu to ensure the Properties option is ticked. If not, click it to toggle the visibility of the window on.

Figure 4 - Adjusting the midtone Level of the Levels Adjustment Layer

In the Properties Window, you will see a histogram with a pointer at either end and a third in the centre. Click the centre pointer with your mouse and drag it to the right. As you do this you will see the image become darker. Notice the Levels Adjustment Layer is affecting the three layers below it in the Layer Stack, causing them all to become darker.

Now in the Layers Window, click the Levels layer and drag it down the Layer Stack to drop it above the Man layer. You should then have the Levels layer sandwiched between the Shadow and Man layers. Notice that when you drop the layer in its new position, it stops affecting the Shadow layer. It’s only the layers below the Levels layer that are affected by the adjustment. If you didn’t notice the change to the Shadow layer, you can drag the Levels layer back to the top of the Layer Stack and then repeat the process.

When the Levels layer is sandwiched between the Shadow and Man layer, it’s still affecting the Man layer and the Background layers, causing them to darken. As we don’t really want to darken the Background layer, we can create a Clipping Mask. This clips the Levels adjustment to the Man layer so that it only affects that layer.

To create a Clipping Mask, right click on the Levels layer in the Layers Window to display a popup menu. In the menu, select the option Create Clipping Mask. You will immediately notice the Background layer becomes lighter as the Levels layer now isn’t affecting it. When creating a Clipping Mask, it’s important to right click on the correct area of the layer in the Layers Window. Depending on where you click in the window, different menu options are displayed. The best location is to right click on the layer’s name.

Because it can be difficult to see the effect of the Levels layer on the man, try moving the centre pointer all the way to the left. This will make the Man layer much lighter and easier to see the effect.

If you click the eye icon on the Levels layer to toggle its visibility off, you will see the Man layer return to its original state. Click the eye icon again to toggle the effect of the Levels layer back on.

Now click the eye icon for the Man layer to toggle the layer’s visibility off. Notice this causes the eye icon for the Levels layer to turn grey. If you then click the eye icon on the Man layer, it makes the layer visible again and the Levels layer icon turns white. Alternatively, if you click the Levels eye icon when it’s grey whilst the Man layer is hidden, it also makes the Man layer visible.

When you create a clipping mask with an Adjustment Layer, the layer it’s clipped to the layer immediately below it in the Layer Stack. You can also identify a clipping mask layer as it has a small downward pointing arrow icon on the layer, just to the right of the eye icon.

To remove a Clipping Mask from a layer, right click on the layer and select Release Clipping Mask from the menu options. As before, be sure to right click on the layer name in the Layers Window.

To finish the exercise, delete the Levels Adjustment Layer. You can do this by clicking and dragging the layer using your mouse, dropping it on the trashcan icon at the bottom right of the Layers Window.

Other Layer Types

We now have three different layer types to consider which are the Fill Layer, Text Layer and Shape Layer. These aren’t used as frequently in photo editing as the Pixel and Adjustment Layers, but we should cover them for completeness.

The Fill Layer is like a Pixel Layer, but it’s filled with pixels of either colour or a pattern. There are three versions of the Fill Layer which are:

Colour – the layer is filled with a single solid colour which you can change.

Gradient – the layer is filled with a gradient where you can define the colours, for example running from black to white.

Pattern – where the layer is filled with a repeating pattern which you can select.

In all three of these examples the Fill Layer acts like a pixel layer in that it covers and hides the layers below in the Layer Stack.

The Text layer is created automatically when you add text to an image using the Horizontal Type Tool. You will find the Horizontal Type Tool in the Photoshop Tools Palette. After clicking the Horizonal Text Tool icon, click on the image and you will see the words Lorem Ipsum appear on a