1. A layer mask in Photoshop is used to control a layer's transparency. It's great if you wish to reveal or
hide portions of a layer using a mask. While you can use the Transparency control to adjust the opacity
of a layer, using a mask gives you a lot more flexibility in what you show, and what you hide. Better still,
you do it all without erasing a single pixel! We'll show you how to get the most out of this function.
As I mentioned at the beginning of this discussion, layer masks allow us to control the
transparency of a layer, but unlike the Opacity option which controls overall transparency, layer
masks allow us to set different levels of transparency for different areas of the layer (although
technically, you could use them to control the overall opacity as well, but the Opacity option
already handles that very well and layer masks are capable of so much more).
How do layer masks work? Well rather than talking about it, let’s just go ahead and use one to
see it in action. Before we can use a layer mask though, we first need to add one, since layers
don’t automatically come with layer masks. To add a layer mask, you first want to make sure
that the layer you’re adding it to is selected in the Layers palette (the currently selected layer is
highlighted in blue), otherwise you’ll end up adding it to the wrong layer. I want to add a layer
mask to the top layer, which is already selected, so I’m good to go. Now if you’re getting paid by
the hour or you simply enjoy taking the scenic route through life, you could add a layer mask by
going up to the Layer menu at the top of the screen, choosing Layer Mask, and then choosing
Reveal All. If, on the other hand, you value your time and no one is paying you for it, simply
click on the Layer Mask icon at the bottom of the Layers palette (it’s the icon that looks like a
filled rectangle with a round hole in the center of it):
Once you’ve clicked on the icon, nothing will seem to have happened in your document, and that’s
because by default, layer masks are hidden from view. After all, the whole point of them is to show and
hide different parts of the layer and it would be pretty difficult to do that if the mask itself was blocking
our view of the image. So how do we know, then, that we’ve added a layer mask if we can’t see it? Easy.
Look back over in the Layers palette, to the right of the preview thumbnail on the layer you added the
mask to, and you’ll see a brand new thumbnail. This is your layer mask thumbnail, and it’s how we know
that a layer mask has been added to the layer:Notice that the layer mask thumbnail is filled with solid
white. That’s not just some random, meaningless color that Photoshop users to display layer mask
thumbnails in. The reason why the thumbnail is filled with white is because the mask itself is currently
filled with white, even though the mask is currently hidden from view. If you want proof that the mask
really is there in your document and really is filled with white, simply hold down Alt (Win) / Option
(Mac) and click directly on the layer mask thumbnail in the Layers palette:
About layer and vector masks
You can use masks to hide portions of a layer and reveal portions of the layers below. You can
create two types of masks:
Layer masks are resolution-dependent bitmap images that are edited with the painting or
selection tools.
Vector masks are resolution independent and are created with a pen or shape tool.

2. Layer and vector masks are nondestructive, which means you can go back and re-edit the
masks later without losing the pixels they hide.
In the Layers panel, both the layer and vector masks appear as an additional thumbnail to
the right of the layer thumbnail. For the layer mask, this thumbnail represents the
grayscale channel that is created when you add the layer mask. The vector mask
thumbnail represents a path that clips out the contents of the layer.
Add layer masks
When you add a layer mask, you can hide or show all of the layer, or base the mask on a
selection or transparency. Later, you’ll paint on the mask to precisely hide portions of the layer,
revealing the layers beneath.
Add a mask that shows or hides the entire layer
1. Make sure that no part of your image is selected. Choose Select > Deselect.
2. In the Layers panel, select the layer or group.
3. Do one of the following:
o To create a mask that reveals the entire layer, click the Add Layer Mask
button in the
Layers panel, or choose Layer > Layer Mask > Reveal All.
o To create a mask that hides the entire layer, Alt-click (Windows) or Option-click
(Mac OS) the Add Layer Mask button, or choose Layer > Layer Mask > Hide All.
In CS5, you can also use the Masks panel (Window > Masks).
Add a layer mask that hides part of a layer
1. In the Layers panel, select the layer or group.
2. Select the area in the image, and do one of the following:
o Click the New Layer Mask button
in the Layers panel to create a mask that reveals the
selection.
o Alt-click (Windows) or Option-click (Mac OS) the Add Layer Mask button in the Layers
panel, to create a mask that hides the selection.
o Choose Layer > Layer Mask > Reveal Selection or Hide Selection.
Create a mask from layer transparency
If you want to directly edit layer transparency, create a mask from this data. This technique is
helpful for video and 3D workflows.
1. In the Layers panel, select the layer.
2. Choose Layer > Layer Mask > From Transparency.

3. Photoshop converts transparency into an opaque color, hidden by the newly created mask. The
opaque color varies greatly, depending upon the filters and other processing previously applied
to the layer.
Apply a layer mask from another layer
Do one of the following:
o To move the mask to another layer, drag the mask to the other layer.
o To duplicate the mask, Alt-drag (Windows) or Option-drag (Mac OS) the mask to other
layer.
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Unlinking layers and masks
By default, a layer or group is linked to its layer mask or vector mask, as indicated by the link
icon
between the thumbnails in the Layers panel. The layer and its mask move together in the
image when you move either one with the Move tool
. Unlinking them lets you move them
independently and shift the mask’s boundaries separately from the layer.
To unlink a layer from its mask, click the link icon in the Layers panel.
To reestablish the link between a layer and its mask, click between the layer and mask
path thumbnails in the Layers panel.
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Disable or enable a layer mask
Do one of the following:
o Select the layer containing the layer mask you want to disable or enable, and click the
Disable/Enable Mask button in the Properties panel (CC, CS6) or the Masks panel
(CS5).
o Shift-click the layer mask thumbnail in the Layers panel.
o Select the layer containing the layer mask you want to disable or enable, and choose
Layer > Layer Mask > Disable or Layer > Layer Mask > Enable.
A red X appears over the mask thumbnail in the Layers panel when the mask is disabled,
and the layer’s content appears without masking effects.
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Apply or delete a layer mask

4. You can apply a layer mask to permanently delete the hidden portions of a layer. Layer masks
are stored as alpha channels, so applying and deleting layer masks can help reduce file size. You
can also delete a layer mask without applying the changes.
1. In the Layers panel, select the layer containing the layer mask.
2. In the Masks panel, click the Pixel Mask button.
3. Do one of the following:
o To remove the layer mask after applying it permanently to the layer, click the Apply
Mask icon
at the bottom of the Properties panel (CC, CS6) and Masks panel (CS5).
o To remove the layer mask without applying it to the layer, click the Delete button at the
bottom of the Masks panel, and then click Delete.
You can also apply or delete layer masks using the Layer menu.
Note:
You cannot apply a layer mask permanently to a Smart Object layer when deleting the
layer mask.
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Select and display the layer mask channel
For easier editing of a layer mask, you can display the grayscale mask by itself or as a rubylith
overlay on the layer.
In the Layers panel, do one of the following:
o
o
Alt-click (Windows) or Option-click (Mac OS) the layer mask thumbnail to view only the
grayscale mask. To redisplay the layers, Alt-click or Option-click the layer mask
thumbnail. Alternatively, click the eye icon in the Properties panel (CC, CS6) or the
Masks panel (CS5).
Hold down Alt+Shift (Windows) or Option+Shift (Mac OS), and click the layer mask
thumbnail to view the mask on top of the layer in a rubylith masking color. Hold down
Alt+Shift or Option+Shift, and click the thumbnail again to turn off the color display.
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Change the layer mask rubylith color or opacity
1. Do one of the following:
o (CS5) Double-click the layer mask thumbnail.
o Double-click the layer mask channel in the Channels panel.
2. To choose a new mask color, in the Layer Mask Display Options dialog box, click the color swatch
and choose a new color.
3. To change the opacity, enter a value between 0% and 100%.

5. Both the color and opacity settings affect only the appearance of the mask and have no
effect on how underlying areas are protected. For example, you may want to change these
settings to make the mask more easily visible against the colors in the image.
4. Click OK.
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Adjusting mask opacity and edges
Use the Properties panel (CC, CS6) or the Masks panel(CS5) to adjust the opacity of a selected
layer or vector mask. The Density slider controls mask opacity. Feather lets you soften mask
edges.
Additional options are specific to layer masks. The Invert option reverses masked and unmasked
areas. The Mask Edge option gives you various controls to modify the mask edges, such as
Smooth and Contract/Expand. For information on the Color Range option, see Confine
adjustment and fill layers to specific areas.
Change mask density
1. In the Layers panel, select the layer containing the mask you want to edit.
2. Do one of the following:
o
o
(CC, CS6) In the Layers panel click the Mask thumbnail. A border appears around the
thumbnail.
(CS5) In the Masks panel, click the Pixel Mask button or the Vector Mask button.
3. In the Properties panel (CC, CS6) or the Masks panel (CS5), drag the Density slider to
adjust the mask opacity.
At 100% density, the mask is completely opaque and blocks out any underlying area of
the layer. As you lower the density, more of the area under the mask becomes visible.
Feather mask edges
1. In the Layers panel, select the layer containing the mask you want to edit.
2. Do one of the following:
o
(CC, CS6) In the Layers panel click the Mask thumbnail. A border appears around the
thumbnail.
o (CS5) In the Masks panel, click the Pixel Mask button or the Vector Mask button.
3. Drag the Feather slider to apply feathering to the mask edges.
Feathering blurs the edges of the mask to create a softer transition between the masked
and unmasked areas. Feathering is applied from the edges of the mask outward, within
the range of pixels you set with the slider.

6. Refine mask edges
1. In the Layers panel, select the layer containing the mask you want to edit.
2. Do one of the following:
o
o
(CC, CS6) In the Layers panel click the Mask thumbnail. A border appears around the
thumbnail.
(CS5) In the Masks panel, click the Pixel Mask button or the Vector Mask button.
3. Click Mask Edge. You can modify mask edges with the options in the Refine Mask
dialog box and view the mask against different backgrounds. For a description of options,
see Refine selection edges.
Or,
A layer mask is simply a way to hide parts of a picture or text.
Even though the masked parts are hidden they are still available if you need them.
In order to use a layer mask you need to understand two things:
black takes away and white adds it back.
When you create a layer mask your foreground and background
colors change to black and white.
If you fill an area on your layer mask with black,
that area will disappear. However you use black,
whether you use a brush, a selection, or a fill, the
area will disappear. The reverse holds true if you use white.
White will reveal all there is in the layer mask while black
will hide all there is in a layer mask.
This is a simple layer mask tutorial.
The purpose of this tutorial is to mask the
lettering so that it looks like it's behind the glass
and so you can have a basic understanding of how a layer mask works.
Alpha Channel
And how they apply to a Clipping Path and a Clipping Mask
Isolating objects in photos using the “extract” or “erase ” tools, is often referred to as Masking.
While there ARE plugins available in Photoshop to make Masking easier, isolating images this
way remains very tedious and time intensive. Mister Clipping mainly isolates images from their

7. backgrounds using a Clipping Path. If necessary or advisable, Mister Clipping can and will also
create an Alpha Channel and/or Masks.
There are two fundamental differences between isolating images using a Clipping Path and the
so-called “Image Masking” mentioned above. Firstly, Masking removes pixels whereas a
Clipping Path is vector based. Secondly, isolating images using Masking allows transparency in
the object. This feature is especially useful when isolating images that include, for example, hair
or glass.
Masking(Clipping Mask)
Masking is a technique recommended for images in which it is difficult to determine what is part
of the subject of the photo and what is part of the background. This could be, for example,
glasses or hair. Masking an object entails the background being removed based on the actual
pixels present, some of which are made transparent. This way, glass remains “glass”, even if you
place it on a different background.
If you would like Mister Clipping to isolate your images using Masking, state it in the
“Additional processing” field while uploading your job. Please note that when Masking images,
they can only be returned in certain image formats, such as .EPS, .TIFF, .PNG and .PSD.
Alpha channel
Another way to isolate images is by using an Alpha Channel. Like Masking, this method is pixel
rather than vector based, but the technique used is different. Every color image contains three or
four color combinations: Red, Green and Blue or Cyan, Magenta, Yellow and Black (RGB and
CMYK respectively).
When isolating an object in an image using an Alpha channel, we create an additional channel
that takes on the shape of the isolated object rather than the color. The Alpha channel is often
used to isolate images with a lot of detail and are made by using the color combination with the
most contrast. Like a Clipping Path, an Alpha Channel can be selected in Indesign, Quark or
Photoshop.
Can Mister Clipping create an Alpha Channel and a Clipping Mask?
Mister Clipping mainly isolates images from their backgrounds using a Clipping Path. If
necessary or advisable, Mister Clipping can create an Alpha Channel and/or a Clipping Mask. In
the “Processing” field of a new job you can determine which technique you would like Mister
Clipping to use. If necessary, this can even be done on an image to image basis within jobs.
Unlike Clipping, Masking requires the image to be placed on a transparent background. This can
only be accomplished if images are uploaded in one of the following formats: .TIFF, .PNG or
.PSD.
For the creation of an Alpha Channel, Mister Clipping will isolate your images using selections
and contrasts in color channels. This requires uploading images in .TIFF or .PSD format.

8. In computer graphics, alpha compositing is the process of combining an image with a
background to create the appearance of partial or full transparency. It is often useful to render
image elements in separate passes, and then combine the resulting multiple 2D images into a
single, final image in a process called the composite. For example, compositing is used
extensively when combining computer-rendered image elements with live footage.
In order to combine these image elements correctly, it is necessary to keep an associated matte
for each element. This matte contains the coverage information—the shape of the geometry
being drawn—making it possible to distinguish between parts of the image where the geometry
was actually drawn and other parts of the image which are empty.
An alpha channel is a type of mask. Masks can be thought of as selections using some or all of
the 256 available levels of gray, instead of a selection outline. Alpha channels define a selection
in black, white, and varying shades of gray pixels. In other words, alpha channels store selections
as 8-bit grayscale images.
In alpha channels, selected pixels are white, black pixels are unselected, and anything in between
is partially selected or partially unselected depending on whether you think the glass is half full
or half empty.
You can create a mask by duplicating a color channel and then editing the channel by using
painting and editing tools and filters. Most graphics geeks refer to this as a channel mask.
If you create an alpha channel from a saved selection, the channel most likely consists of just
black or white pixels. If you have a feathered or even an anti-aliased selection, you may have a
few gray pixels. If you create an alpha channel by duplicating and editing a color channel, your
alpha channel most likely contains varying shades of gray pixels as well.
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