A simple tutorial on masking in Photoshop

For some reason, when I was first trying to learn how to use masking in Photoshop, it was difficult. I don’t know what I was missing or if the tutorials I found weren’t easy to follow, but either way, it took a combination of trial and error before I really grasped the concept.

I know there are literally thousands of tutorials on masking in Photoshop out there, but I have a few friends who were looking for a simple way to understand it and had asked me for help in showing them just how its done.  Hence I’m writing my own quickie guide to simple masking which not only gives you a great tool in a broad area of photo processing, but can also jump your HDR finished products up a few notches.

Layers and Masking

Photoshop has the ability to have layers. You can have multiple versions of an image on different layers (or anything else for that matter, but for now, we stick to different versions of the same image). Layers are exactly what you think: There is a top layer, middle, and bottom, plus anything anything else in-between. They are in order…top to bottom.

In layman’s terms, masking is simply allowing a lower layer to show through into an upper layer in varying degrees of opacity and flow.

One of my images from Amsterdam was done using a combination of black and white, HDR and masking. I had never processed a shot like this before, but for some reason when I was working on it, I knew it needed to be done this way.

Masking Tutorial

Below is the first image I was working with…the HDR version:

Here is the second, a simple black and white of the same scene:

Now open both in Photoshop, take the black and white image, copy all and then paste it into the HDR image. Then ensure the layers look like image below, with the black and white as the top layer:

Click on the Top Layer (Black and White) and find this little icon at the bottom, which is the masking button:

Press it and now you’ll have something like the image below:

Now you want to ensure your focus is on the masking area, so click on that newly created white box. By default, when you create the masking layer, it automatically focuses on it. But sometimes you may go to work on another layer and then want to come back, and it’s easy to forget to click on the masking layer.

Next you want to make sure your default Foreground Color is BLACK and your Background Color is WHITE. See below:

What you need to remember, which is key to masking is this:

BLACK = ALLOWS the lower layer to come through.

WHITE = DISALLOWS the lower layer to come through.

So now you are ready to do some masking. Click on your paint brush tool seen below:

Below are the base brush settings I use when first starting to mask in the lower layer. The Opacity and Flow are all mid-range. This forces you to take your time in what you allow to come through. Yes, you may have to paint over an area multiple times to get the entire lower layer to show through, but this way you have more control. You can play with this and do whatever you like.

Use the bracket keys (  [   ]  ) to make the brush bigger and smaller on the fly to help you speed through it. This allows you to work on tiny details or do a wide brush over an entire area of the image:

Now the final step is to just start painting over the areas with your brush using the current Foreground Color (Black). The image below shows that I’ve painted over the car with the brush until I’ve allowed the entire color of the car to come through to the black and white layer.

NOTE: Masking only works on the layer immediately below the masked layer. So if you want to do more than two layers, you need a mask on every layer and paint on every layer to let everything through.

If you look at the image below (click on it for a larger, clearer view), you can see the Masking Layer now has a large black splotch in the middle of it. That is the area that has been painted over to let the lower layer come through.

If you screw up and accidentally let something through you don’t want, switch to the color WHITE and start painting over your mistake area. This has the effect of restoring that area to normal.

And thus we have the final image below:

The final effect is putting the focus of your vision on the car itself, which was the main reason for snapping the photo in the first place. But using a combo of HDR, B&W and masking really adds emphasis to what you want the viewer to see.

Other Ways to Use This

The tutorial above was a simple way to show you how masking works. But doing the HDR + B&W is not something I ever really do aside from this photo. Where I DO use it a lot is in the final steps in processing my HDR photos. Here are two other ways I use it:

  • Noise Reduction: On almost every HDR I do, I always have a lower layer that has all the noise reduced in varying degrees. Then I mask in the smoothed areas in the places I need it in the top layer. I use this a lot with clouds in my weather shots. They almost always have noise, so reducing that and then masking it in allows your clouds to be awesome and smooth, but your mountains, trees and foreground elements to keep their details. And obviously, I only mask in the areas of clouds that have noise, not all of it. Keep that image as detailed as you can!
  • Object Movement: Sometimes you can’t take brackets fast enough to account for movement of objects. Sometimes even Photomatix isn’t powerful enough to eliminate those movements. Just recently I used this on some clouds that crossed the sky with amazing speed. Photomatix couldn’t fix it. So I did a single image HDR, put it on a lower layer and just masked in the areas of the clouds that had the most obvious movements. Bingo, fixed!

I’m sure people use masking for other things…if you do, let us know in the comments below!

Basically that’s the idea behind masking. Hopefully it was clear and concise enough for newer Photoshop users to grasp and be able to apply to their post-processing.

When I was learning how to create HDR photos, two factors made my final images jump from just average to a heckofalot better:

  1. Noise Reduction
  2. Masking

Hope this helps someone out there!