Layers are a vital part of using Photoshop and are one of the main things which distinguish Photoshop from RAW editors such as Lightroom. Layers provide the capability to work with entire images or any part of an image. They also enable the use of other types of content such as text. They work best in conjunction with masks, but more of that later.
What are layers?
When you load any Photoshop (.psd) image into Photoshop, it will contain at least one, and often more, layers. Each layer is a separate ‘slice’ of the image and can include different types of content. Together, the layers will produce the final image. They appear in a ‘stack’ one above the other. The order of layers is very important as the content of any layer will hide, partially hide or have an effect upon other layers which are lower in the layer stack.
In the example below, the square image headed Photoshop View, shows a stack of layers. The Stacked View illustrates how these layers stack together. The Layers Panel graphic shows the arrangement of layers (outlined in yellow) in the square Photoshop View.
The square image has the following layers:
- top layer is red text
- next is a blue circle
- then an orange triangle
- the square is green
In the uppermost 3 layers, only the text, the circle and the triangle are visible. The rest of these layers is completely transparent. Where there is content in these layers, it will hide whatever is directly underneath.
What can you do with Layers?
Layers enable all sorts of possibilities and they give a much greater level of control to the post-processing workflow. Here are just some of the things you can do with layers:
- work with an entire image on a single layer (not recommended!).
- work with different parts of an image on separate layers (highly recommended).
- affect a wide range of aspects such as tonality and colour by using adjustment layers.
- blend layers together to lighten, darken or add contrast to images.
- blend multiple exposures for High Dynamic Range subjects.
- merge multiple exposures in a panorama.
- create composite images from two or more originals.
- add text, frames and other graphic content.
- edit non-destructively.
All of these will be covered in module 7, ‘Using Layers and Masks’ and illustrated in Module 8, ‘Putting it all together’.