LESSON 6 – Masking

CIOS F255 - University of Alaska Fairbanks


In an earlier assignment, we worked with several of Photoshop’s selection tools: the marquee, the lasso, and the magic wand, for example. You also may have been working with the eraser tool quite a bit. While these tools are valuable for making selections, you will undoubtedly encounter situations where they don’t perform as well as you’d like. Some of you have already been working in the select and mask interface quite a bit too so here’s another chance to perfect those selections!

Masks and channels are a more sophisticated way of making selections. You can think of a mask like the use of masking tape when you’re preparing to paint your house. Have you ever painted the trim around your windows? You probably began by “masking off” the areas you didn’t want to get paint on. That’s exactly the concept of creating a mask in Photoshop  –  you’re protecting the areas you don’t want to get paint on! The select and mask interface has many options you can use to get your selections just right.

And after you spend 20 minutes making a precise selection, isn’t it frustrating to deselect, knowing you’ll have to start over again if you want to re-select the same object? Alpha Channels give you a solution! Alpha Channels are essentially just saved masks that you can use again in the future.

Tools you should be using for this lesson include:  layer masks, alpha channels, selection tools,  Select & Mask  interface/refine tools

In this lesson, you  will NOT use the eraser tool or delete key!  



Understanding masking and channels is tricky and takes some time and lots of exploration.

The reason to always use masks rather than deleting or copy/pasting selections into a layer is that it is a non-destructive technique that allows for further refinement and modification on down the road. You can always go back and edit or refine the mask or reveal areas that you had originally masked out of the visible part of the layer.

A masked layers should look like:


You can see that the goat in a bucket layer has a mask to the right of it. The areas that are black have been masked out (black conceals) and the areas of white reveal.

In the layer panel itself, different things happen when you click on the icon of the layer image (goat) and the mask (black/white cutout area). If you click on the mask icon on a layer, you can paint (using the paintbrush tool) in black or white (only) to modify what is being masked out.

Here, I have used the brush tool and painted (in white) on the mask (click on mask icon on layer) to reveal some areas of straw. Notice how the mask icon has changed:


Puppet Warp Tool

I’ve also included a video for using the Puppet Warp tool. This is a tool that lets you fine-tune your images when needed and might come in handy for the assignment this week.


Masking With Brush Tool

Select and  Mask tool

 Puppet Warp

Masking with Alpha Channels


Assignment 6a

Select the garden gnome and place him in a more natural setting. Below are a number of images for you to choose from (feel free to integrate your own photos as well but a gnome is required and at least three images). Click on images below and they will open in a focus window, then save image to your computer by dragging/dropping onto your desktop or folder or right-click-save as. You may need to rotate the image and you will need to transform your selections to fit as well. Also, feel free to colorize for artistic touch. Some of the images need exposure corrections.
credits (last two images): Wikimedia Commons: Ron Shirt (English Garden) and  Bullenwächter (Clay Gnome)

Experiment with  Masks  and  Alpha Channels. Use Select & Mask interface  to work on the details of your selections. Try Puppet Warp tool.

Your final product should contain a  minimum of three image layers, which display your use of masks and alpha channels.  Feel free to use more than three layers and include as many flowers or other aspects of the gnome’s surroundings as you wish.

Remember that you can resize the gnome as necessary to make him fit in his new home. Your goal is to make the final image look as natural as possible.

Sometimes students want to change the overall colors so that the gnome is living in a sort of psychedelic flower garden. This type of approach is fine as long as all the elements match the aesthetic approach – who knows how gnomes see the world anyway!

Keep detailed step-by-step notes of the steps you take.

Important for this assignment:

  1. Do not use the eraser tool,
    Do not use the delete key,
    Do not copy/paste a selection onto another layer!
    (points will be taken away!)
  2. You must use  layer masks  to hide areas of layers that you don’t want.
  3. Describe your use of the Select & Mask  interface.
  4. Try out Puppet Warp at least once and describe your experience  using  it.
  5. Try creating a mask using an Alpha Channel (find the one with most contrast)

When you’re happy with your project:

  1. Save your Photoshop file (.psd –  leave the layers intact).
  2. Take a screenshot of your image with all the layers showing
  3. Upload your optimized files to a new post on the class blog (give it a creative and unique title) along with your step-by-step notes. Tell us what challenges you faced. Which techniques worked best for you in making your selections? What pitfalls if any?

Assignment 6b – Inspiration Research

Do some searching on the Internet for images that you think have been manipulated with Photoshop and that inspire you creatively. Download at least 2 images to your computer and then upload them to a post (title it “6b research – Your Name”). Tell us briefly why they inspire you, what technique they employ that you would like to learn, or if you had the chance to create something similar how would it be different.

On the lower right side of our blog page are links to a Pinterest collection of images I’ve found, have a look at these if you like but please find your own images elsewhere.


Please log into Blackboard and take Quiz #6 – Masking


Do discussion this week. Next week we’ll be going into a little more depth with discussion and you’ll be doing an informal critique of each other’s gnome posts. Critiques are challenging to do well but can be really valuable for everyone, as it requires that you look critically at what you have created and what others create as well. Sometimes it’s hard to see the forest for the trees also and having someone else take a look at your work to give their helpful feedback can be a fresh perspective on little or big things you miss.