Snapper’s Tip of the Month: Mask Basics in Photoshop CS5

by Snapper Earl

Posted: March 28, 2011

OK, for any of you good readers who were attracted to this tip thinking that you could get a head start on a cool Halloween costume, I’ll apologize in advance. This article is on Adobe Photoshop masks - what they are and how to use them in CS5.

Those of you have done some painting (think Bob Vila, not van Gogh) may have had some experience using masking tape to protect areas from over painting or to create a separation between areas of different color. Masks in Photoshop are similar in their functions but easier to modify for specific uses. Masks can be used to apply changes to very specific areas, with the option of controllable opacity, kind of like semi-porous masking tape. Additionally, masks can be saved for reuse or used in separate channels for the highest degree of control.

Here’s a shot of a committed harmonica player against a bland background.  I want to use this photo for an advertisement so I will give him more exciting surroundings.

I’ll use the Quick Selection tool and create a mask to isolate the musician from the background. Here are my Option Bar settings: 

Here is the image after I have applied the Quick Selection tool to mask the musician: 

By pressing the option key while using the Quick Selection

tool I can roughly deselect some of the shadow area that was accidentally included behind him. 

I’ll click on the Masks Panel and choose Add A Pixel Mask. 

Here’s the result:  A new layer with the selection in white and the deselected area shown in black appears in the Layers Panel. It’s a decent mask with room for improvement. There are some shadows and other problems but I will Refine these away in the Masks Panel.

Select Mask Edge and the Refine Mask box opens. 

Clicking on the arrow next to the little preview gives you options for viewing the effects of your adjustments

I’ll choose to view it on a white background; I think it makes the subject nicely visible.

I’ll use the sliders in the Adjust Edge section to create a smooth, natural looking edge. I left the Feather slider alone because I want a definite separation between subject and background.

The Contrast Slider will make the edge more abrupt or ‘edgier.’ Adjusting the Shift Edge slider will expand or contract the entire edge of the mask. 

In the Output area I’ll select Decontaminate Colors, and Output To New Layer With Layer Mask.  If I zoom in on the smoothed over hair I can use the Refine Radius Tool and brush out any white area covering the wisps of hair I want included. You can use the ]-key to increase the brush size or the [-key to decrease it.

Photoshop will adjust the edge and eliminate the background as you work, and it does a good but not always perfect job. If any background remains, use the Erase Refinements tool that lives behind the Refine Radius tool and brush out the background. Hit OK when you are satisfied.

I added another layer under the Mask Layer after deleting any unnecessary layers that might exist, and I’ll add a super exciting bull’s-eye gradient effect to make the harp player stand out even more. I could add some text, background singers, Royal audience, etc., but I’ll leave it alone for now and save the file with the mask layer included for just that purpose.

And here's the finished product.

Available for Weddings, Parties, and Bar Mitzvahs...