Photoshop CS6 Fundamentals: Layer Mask Creation Strategies
Adapted from Understanding Adobe Photoshop CS6: The Essential Techniques for Imaging Professionals (Peachpit Press)
By Richard Harrington
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There are many different approaches to creating Layer Masks.
The approach you should take will vary based on your source
image. Letís try using three different images and
techniques to perfect your Layer Masking ability.
Using a Gradient as a Mask
When youíre designing, you may need to gradually blend the edges of an image. This can be
easily accomplished by combining a Layer Mask
and a gradient. Letís give it a try.
- Download the archive containing Gradient_Mask.tif and the other files for this tutorial and then open it.
- Duplicate the Background layer by pressing Command+J
- Select the top layer and choose Image > Adjustments >
- With the topmost layer active, click the Add layer mask button
at the bottom of the Layers panel (it looks like a rectangle with
a circle inside). A new, empty Layer Mask is added to the layer.
- Press G to select the Gradient tool.
- Press D to load the default colors of black and white.
- From the Options bar, choose the black-to-white gradient. If
itís not available, choose Reset Gradients from the Gradient
- With the Layer Mask selected, click and drag
to create a new linear gradient going from
top to bottom in the document window.
- The new Layer Mask creates a gradual blend
from the grayscale version to the colored
The gradient mask allows the image to blend between the
grayscale and color image.
This technique of adding a mask can also be
used on one layer to create a gradual fade to
transparency or to a different layer stacked
Using a Channel
Often, a channel will get you very close to
a perfect Layer Mask. This technique works
particularly well when the subject is against a
high-contrast background (such as a sky or a
wall), and it works very well with fne details like
hair. The image can be masked so it is ready for
integration into a composite image. For example,
a masked image could be used to add a palm tree
to another photo. Letís give it a try.
- Open the Channel_Mask.tif file.
- Switch to the Channels panel and examine the Red, Green,
and Blue channels.
Look for one with high contrast from the background.
Although all three channels are fairly high contrast, the
Blue channel stands out the most.
- Duplicate the Blue channel by dragging it onto the New
Channel icon at the bottom of the Channels panel (it looks
like a pad of paper).
- Rename the new channel Selection by double-clicking
- With the Selection channel selected, press Command+L
(Ctrl+L) to invoke a Levels adjustment. Levels is a powerful
command that allows you to adjust the gamma (gray) point as
well as the black and white points.
- Move the black slider to the right, setting the Input Level to
around 60. The black in the channel should get crisper.
- Move the white slider to the left, setting the Input Level to
around 190. The gray areas in the channel should switch to
- Move the middle (gray) slider to refne any
gray spots in the channel. A value of 1.5
should be approximately correct.
- Click OK to apply the Levels adjustment.
- Command-click (Ctrl-click) on the Selection
channelís thumbnail to load the selection
(youíll see the marching ants).
- Choose Select > Inverse to reverse the
selected area from the sky to the palm tree.
- Turn on the visibility for the RGB channels
by clicking the RGB composite channelís
visibility icon. Turn off visibility for the
- Switch to the Layers panel.
- Click the Add layer mask button at the bottom of the Layers
panel to turn the palm tree into a layer with a mask added.
This command uses channel data to create
a new alpha channel. You can then refine the channel to create an
accurate selection. You can also take this one step further to make
a high-quality Layer Mask. Letís give it a try.
- Open the file Calculations.tif.
- Turn the Background layer into a floating layer
by double-clicking its name in the Layers
panel. Name the layer Banana Tree.
- Call up the Channels panel and closely
examine the channels for a high contrast
between the tree and the background.
Although all three channels have contrast
between the sky and the tree, the Blue channel has the best.
- Invoke the Calculations command by choosing Image > Calculations.
- Set Source 1 to the Blue channel, set Source
2 to the Red channel, and select the Invert
check box. The Red channel differs most
from the Blue channel in this image, so it
will create a good matte.
- Experiment with different blending modes
so you get a clearer separation between the
tree and the sky. In this case, the Vivid Light
mode works best to create a new channel.
- The new channel will need a little touch-up.
You can get the channel near perfect with
a Levels adjustment. Press Command+L
(Ctrl+L) to invoke the Levels dialog box.
- Adjust the black, white, and gray points for Input Levels to
improve the matte. Click OK when youíre satisfied.
You then need to reverse the channel so the area you want
to discard is black. Press Command+I (Ctrl+I) to invert the
- Soften the selection by blurring it. Choose Filter > Blur >
Gaussian Blur, set it to a value of 1 pixel, and click OK.
- Load the channel as a selection by Command-clicking
(Ctrl-clicking) the channelís thumbnail.
- Turn on the visibility icon for the RGB channels and turn it off
for the alpha channel.
- Switch to the Layers panel and select the Banana Tree layer.
- Click the Add layer mask button to apply a mask to the
Tip: The Masks Panel Is Essential
The Masks panel offers several other useful commands. You can load a
mask as a selection, apply a mask, disable its visibility, or discard it. Additionally, you can use the Color Range or Invert command to further refine
the selection. The Masks panel consolidates all the masking commands into
a single location, which can save you valuable time.