Adobe Photoshop is a great tool for those who want more options when it comes to post-processing than what you get in Lightroom or other RAW-editors. With Photoshop the possibilities are almost endless so it’s not strange that it seems slightly overwhelming in the beginning. Perhaps you’re in that state right now; wanting to step up your processing but Photoshop seems so complicated that you feel like giving up. Don’t worry though – it might take some practice and a lot of trial and error but you’ll soon see great improvement.

Layers & Layer Masks are two of the biggest advantages you find in Photoshop over any RAW-editor. It’s also here that it starts becoming somewhat confusing for some. However, understanding Layers and Layer Masks is crucial for you to fully exploit the power of this software.

Understanding Layers

So, what exactly are layers and why are these so important to understand?

Simply put, layers are images put on top of each other. When you add one layer on top of another, the top layer will be on top of the hierarchy and the one that’s visible. In other words, if you have three layers, the first blue, the second red and the third (top) is green, the image you’re looking at is green as it’s the top layer. If you erase part of the top layer, however, it will begin to reveal the layer beneath (red).

Layers for Landscape Photography

For photography, most of the time you’ll use layers in a little different way (yes, I’m about to make this a little more confusing but stick with me!) Rather than just working with layers as “images”, we rely more on what we call Adjustment Layers. These types of layers are transparent until you alter the adjustment. A common example is the Curves Adjustment Layer. By simply opening this adjustment (Create New Fill or Adjustment Layer -> Curves) you haven’t actually made any changes yet and the new layer appears invisible. However, when you start making an adjustment to the Curves layer, let’s say you make an S-Curve to increase contrast, that particular adjustment will be visible. If you then create another Adjustment Layer, this time Photo Filter, the previous adjustment will still be visible and the new adjustment will be added on top of it.

Layers & Masks in Photoshop

A workflow such as the one above, where you mostly rely on Adjustment Layers, is known as a non-destructive workflow. Simply put, that means you can go back and make an adjustment to any of the Adjustment Layers you’ve made and the effect will be visible. On the other hand, if you’re not working with Adjustment Layers but instead with Merged Layers, you aren’t able to go back and change the adjustments as these type of layers are “images” put on top of each other, meaning that each layer completely hides the one below.

Using Layer Masks

You may not always want to make adjustments to the entire image. In those scenarios, Layer Masks prove to be one of the real benefits of working in Photoshop.

As explained above, the top layer is always at the top of the hierarchy and will conceal the layers beneath. If you want to remove an adjustment from a specific area, you could use the erase brush directly on the layer but this isn’t a particularly good solution. Instead, you can add a Layer Mask to the layer.

The Layer Mask appears as a white rectangular box that’s shown next to the layer in the Layer Panel. By default it’s white but it can represent two true colors: Black & White plus the shades of gray in between.Layer Mask

A white Layer Mask means that the entire layer/adjustment is visible on top of the layers below. A black Layer Mask, however, means the opposite; the layer and its adjustments are invisible.

Remember this phrase: White Reveals and Black Conceals

To add white or black to the Layer Mask, the most useful tool is the Brush Tool (B). Select a suitable size, set the brush color to black, make sure the Layer Mask is selected (click on it) and paint the areas you don’t want to be adjusted with black. As you can see, the image itself is not becoming black but the adjustment that layer has made is being concealed; it’s only the Layer Mask that’s become black in these areas.

Layers & Masks in Photoshop

Layer Masks have several benefits and, personally, I use them in almost every single layer I create when processing a file in Photoshop. Here are some of the scenarios where I use a Layer Mask:

  • When adjusting the color balance to a specific tonal range (such as adding blues in the shadows)
  • Blending multiple images together
  • Removing an adjustment from an area I want untouched.

The Challenges of Layer Masks

Regardless of how useful Layer Masks will be for your performance in Photoshop, it’s important to understand that they aren’t perfect right away. Just painting with a brush on the Layer Mask will be fine in many scenarios but you’ll soon see that you get a certain amount of haloing and bleed on the images. Since you’re manually painting on the Mask, it’s easy to get a little sloppy and paint slightly above the edge or outside the area you want to reveal or conceal. This often becomes a problem later on as it’s a very visible mistake.

Instead of manually using the brush (though it’s completely fine in certain scenarios), I recommend learning how to use Luminosity Masks once you’ve got a basic understanding of Photoshop. These are more refined selections which are made to avoid those unwanted mistakes.

An example of when using Luminosity Masks rather than manually painting on the Layer Mask is beneficial is when you want to make a targeted adjustment. I often adjust the color balance in certain areas of the image; I might add a little blue in the darkest shadows. When doing this, I’ll use the Luminosity Masks to get a specific mask that only targets the darkest shadows, so I don’t have to worry about brushing a little too far into a brighter area I don’t want to be adjusted.

I know that Layers & Layer Masks might sound a little confusing if you’ve just opened Photoshop for the first time but I encourage you to spend some time playing around with them. These are essential in your use of Photoshop and you won’t be able to benefit from this software unless you understand them.