Digital Art I
Photoshop Tutorial 4
Masks and Channels
The following tutorial will review how to:
• Use the masking function:
Create and remove background
Refine a mask to include complex edges
Create a quick mask to make changes to a selected area
Edit a mask using the Properties panel
• Use the mask function:
Saving a selection as an alpha channel
Viewing a mask using the Channels panel
Loading a channel as a selection
Isolating a channel to make specific image changes
• Use the Text tool:
Creating a clipping mask from type
Making a clipping mask and applying a shadow
NOTE: Always work on a copy of the original image! This is to insure that the original
is left untouched in case you mess up!
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Restore the preferences for Photoshop to the “default” settings.
Working with masks
The masking function in Photoshop, isolates and protects parts of an image. When you
create a mask based on a selection, the area you haven’t selected is masked, or
protected from editing.
With masks you can:
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Create and save selections to be used again.
Use masks for complex editing asks (color changes or filter
effects).
Create a temporary mask called a Quick Mask.
Masking tips
Mastering masks can help you work more efficiently in Photoshop. Since masks are
nondestructive, you can edit the mask later without losing the pixels that they hide.
• Always be aware of the selected color in the Tools panel (color swatch area).
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Black hides.
White reveals.
Shades of gray partially hide or reveal.
The darker the gray, the more is hidden by the mask.
Types of masks
Layer Mask: Is like an Alpha channel, but is attached to a specific layer. A layer mask
controls which part of the layer is revealed or hidden. It appears as a blank thumbnail
next to the layer thumbnail until you add content to it; a black outline indicates that it
is selected.
Vector Mask: Is a layer mask made up of vectors, not pixels and is resolution
independent. Vector masks have crisp edges and are created with the pen or shape
tools. They don’t support transparency, so their edges can’t be feathered.
Clipping Mask: Is applied to a layer and it confines the influence of an effect to specific
layers, rather than to everything below the layer in the layer stack. Using a clipping
mask clips layers to a base laye; only that layer is affected.The name of a clipped base
layer is underlined.
Channels
Photoshop uses Channels to store an image’s color information. Unlike layers, channels
do not print. Permanent masks are stored as special grayscale channels called alpha
channels. They restrict editing to a specific channel and are useful for making intricate
fringed, or wispy-edged selections. You can create a Channel on a dominant color in an
image or a pronounced contrast in an isolated channel (like a subject and the
background).
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Creating a mask
You’ll use the Quick Selection tool to create the initial mask in order to separate the
model from the background.
1) Go into the menu for File>Open navigate through the computer to find the image you will
be working on titled lesson_4_photoshop.psd
2) Select the Quick Selection tool. In the Options bar, set up the brush with a size of 15 Pixels
and a hardness of 100%.
3) Go into Layer 0 and select the model by clicking and dragging the Quick Selection tool
around the entire figure. You’ll notice that it’s easy to select his shirt and face, but not all of
his hair.
4) With the model still selected, click the Add Layer Mask button (at the bottom of the Layers
panel), to create a layer mask.
5) The selection now becomes a pixel mask sitting on a transparent background.
Refining the mask
The Quick selection tool couldn’t quite get all the fine detail areas of the hair. You’ll now learn
how to smooth the mask and then fine-tune the area around the hair.
1) Go into the Window menu select Properties to open the Properties Panel.
2) Make sure the icon for the layer mask (black and white silhouette of the man) is selected in
the Layers panel.
3) In the Properties panel click Mask Edge. The Refine Mask dialog box opens
4) In the View Mode area of the dialog box, click the arrow next to the preview window.
Choose On Black from the pop-up menu. The mask appears against a black background,
which makes it easier to see the edge of the white shirt and face.
5) Use the Zoom tool within this dialog box to zoom into the hair and reposition the image with
the Hand tool (within this dialog box) if necessary.
6) In the Adjust Edge area of the dialog box, move the sliders to create a smooth unfeathered
edge along the shirt and face. As you more the sliders the white background should begin to
feather and decrease. (The optimal settings depend on the selection you created). Do the
following settings as a base mark:
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QuickTime™ and a
decompressor
are needed to see this picture.
7) With the dialog box still open, go to the Layer Output area of the dialog box, select
Decontaminate Colors. In the Output To menu select New Layer With the Layer Mask
from the dropdown.
8) With the Refine Mask dialog box still open, select the Zoom tool within the dialog
box. Zoom into man’s face.
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9) With the Refine Mask dialog box still open, select the Refine Radius tool
within
the dialog box. You will use it to paint out and white areas that remain around the nose
and lips. You can press the left bracket [ to decrease the brush size or the right ] bracket to
increase the brush size.
10) When you are satisfied with the mask around the face, click OK.
A new layer named Layer 0 copy appears in the Layers panel. You’ll use this layer to add the
spikes to the mask of hair.
1) With the Layer 0 still selected, click Mask Edge in the Properties panel to open the
Refine Mask dialog box again.
2) From the View Menu, select On White. The black hair will display better against a
white background for editing. If needed, use the Zoom tool from this dialog box.
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3) Select the Refine Radius tool within this dialog box. (Use either of the bracket
keys to increase/decrease your brush size). Begin brushing along the top of the hair,
high enough to include the spikes. Then, paint along the right side of the head to to
pick up any fine protruding hairs.
4) Under the Refine Radius tool select the Erase Refinements tool.
5) Select Decontaminate Colors, and move the Amount slider to 85%. Select
New Layer With Layer Mask from the Output menu. Click once or twice in each
area where the background color shows. When you erase an area, the Refine Mask
feature erases similar colors, cleaning up more of the mask for you. Be careful not
to erase the refinements you made to the hair edge. When done Click OK.
6) In the Layers panel, make the Magazine Background visible.
Creating a quick mask
You’ll create a quick mask to change the color of the frames of the man’s glasses.
1) If it isn’t already hidden, hide the Magazine background layer. Then delete the
Layer 0 and Layer 0 copy layers by selecting them and clicking the trash can
at the bottom of the Layers panel. Click Yes to Delete when prompted. NOTE: You
do not need to apply the mask to the current layer because Layer 0 copy 2 already
has the mask applied.
2) Double-click the Layer 0 copy 2 layer to rename it Model. Hit the return key
after typing.
3) Click the Edit In Quick Mask Mode button in the Tools panel (By default you have
been working in the Standard Mode).
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In the Quick Mask mode, a red overlay appears as you make a selection, masking the
area outside the selection. You can apply changes only to the unprotected area that is
visible and selected. Photoshop automatically defaults to Grayscale mode with a
foreground color of black and a background color of white. When using the painting tool
in Quick Mask mode, be aware of the below:
• Painting with black adds to the mask (the red overlay). This decreases
the selected areas.
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• Painting with white erases to the mask (the red overlay). This increases
the selected areas.
1) In the Tools panel select the zoom toll to zoom into the model’s glasses. Select the
Brush tool.
2) In the Options bar, make sure the Normal is selected in the Mode section. Open
the Brush pop-up panel and select a brush with a diameter of 13 px. Click
outside the panel to close it.
3) Paint the earpiece of the frames. The area you paint will appear red creating a mask.
4) Continue painting the earpiece and frame around the lenses. Reduce the brush size
to paint as needed.
5) When done painting, click the Edit Standard Mode in the Tool panel to exit Quick
Mask Mode. You will see the unmasked areas that are selected.
6) Go into the Select menu and select Inverse.
7) Go into the Image menu and select Adjustments>Hue/Saturation.
8) In the Hue/Saturation dialog box, change the Hue to 70. A new green color appears
filling the frames. Click OK. Deselect.
SAVE YOUR WORK!
Manipulating an image with Puppet Warp
The Puppet Warp feature gives you flexibility in manipulating an image. You can
reposition areas, such as hair or an arm, just as if you were pulling strings on a puppet.
You’ll use the Puppet Warp to tilt the model’s head back.
1) Select the Model layer. Zoom down to see the whole model. Go into the Edit menu
and select Puppet Warp. A mesh appears over the visible areas in the layer (over
the model). You’ll use the mesh to place pins where you want to control movement
or non-movement.
2) Click around the edges of the shirt. Each time you click, Puppet Warp adds a pin.
Approximately 10 pins should work. The pins you’ve added around the shirt will keep
it in place as you tilt the head back.
3) Select the pin at the nape of the neck. A white dot appears in the center of the pin
to indicate that it’s selected.
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4) Hold down the Option key. A larger circle will appear around the pin and a curved
double arrow appears next to it. (If you move your mouse slightly with the Option
key down, a scissors appears allowing you to delete a pint).
5) With the double-head arrow appearing, drag the pointer to rotate the head
backwards. You can see the angle of rotation in the Options bar; or for more
accuracy, you may enter a value of 135 in the rotation field.
6) When you are satisfied with the rotation, press the Return key.
Working with channels
Channels work similar to Layers in that they allow you to access specific kinds of
information. Where Layers store painting and effects, Channels store the following:
• Alpha channels: Store selections as grayscale images.
• Color channels: Store information about each color in an image; an RGB
image would have red, green, and blue channels.
Using an alpha channel to create a shadow
To create a shadow for the mask you created you’ll make an alpha channel.
1) In the Layers panel, hold down the Control key and click on the icon for the model
(small icon showing the full color photo).
2) In the menu and select, Select Pixels. Go into the Select menu and select Save
Selection. In the dialog box, make sure New is chosen in the Channel menu. Then
name the channel Model Outline and click OK. (When you eventually go to the
Channels Panel in a few steps, a new channel will have been created title Model
Outline).
3) With the model still selected, click the Create A New Layer at the bottom of the
Layer panel. Drag the new layer below the Model layer; double-click on the name
and rename it to Shadow.
4) With the Shadow layer selected, go into the Select menu and select Refine Edge.
In the Refine Edge dialog box move the Shift Edge slider to +36 %. Then click
OK.
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5) Go into the Edit menu and select Fill. In the Fill dialog box, choose Black from
the Use menu and then click OK.
6) In the Layers panel, change the layer Opacity to 30%.
7) Go into the Select menu and Deselect.
8) Go into the Edit menu and select Transform>Skew. Rotate the shadow by hand,
or enter -15° in the Options bar. The drag the shadow to the left, or enter 845 in
the X field in the Options bar. Click the Commit Transform button (to check it off), or
press Enter or Return keys.
Adjusting an individual channel
You will next adjust the model’s hair for highlights. First you will have to convert the
image to CMYK mode so you can take advantage of the Black Channel.
1) Select the Model layer.
2) Go into the Image menu and select Mode>CMYK Color. Click don’t merge in the
dialog box (you want your layers to be retained). Click OK in the next dialog box.
3) Hold down the Option key and click on the eye icon in the Model layer to hide all
the other layers.
4) Select the Channels tab (behind the Layers panel). In the Channels panel select
the Black Channel. Hold down the Control key and select Duplicate Channel
Name the Channel Hair.
Individual channels appear in grayscale. If more than one channel is visible in the
Channels panel, the channel appears in color.
1) Make the Hair Channel visible and hide the Black Channel. Go into the Hair Channel
and select Image>Adjustments>Levels.
2) In the Levels dialog box, adjust the levels to move the Black arrow to 85, Gray
arrow (Midtones) to 1, and White arrow to 165. Click OK.
3) With the Hair channel still selected, go into the Image menu and select
Adjustments>Invert. The channel appears white against a black background.
4) Select the Brush tool and switch the Foreground and Background colors so that
the Black swatch is selected (to do this click on the double-headed arrow next to
the swatches). Paint over the glasses, eyes, and anything else that isn’t hair.
5) Click the Load Channel As Selection icon at the bottom of the Channels panel.
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6) Select the Layers tab. In the Layers panel, select the Model layer.
7) Go into the Select menu and select Refine Edge. In the Refine Edge dialog box,
move the Feather slider to 1.2 pixels, and then click OK. DO NOT deselect!
8) Use the Zoom tool to zoom out if needed. Go into the Image menu and select
Adjustments>Hue/Saturation. Select Colorize and then move the sliders as
follows. When done click OK.
QuickTime™ and a
decompressor
are needed to see this picture.
9) Go into the Image menu and select Adjustment>Levels. In the Levels dialog
box, move the sliders so that the Black slider is positioned where the blacks
peak, the White slider where the whites peak, and the Midtones in between.
Then click OK. (Values are 58, 1.65, and 255; your values may vary).
10) In the Layers panel, make the Shadow and Magazine layers visible. Deselect and
save.
The text tool
When you add type to an image in Photoshop, the characters are composed of pixels
and have the same resolution as the image file. However Photoshop preserves the
vector-based type outlines and uses them when you scale or resize type, save a .pdf or
.eps file, or print the image to a postscript printer. Type is produced with crisp
resolution independent edges. You can apply effects and styles to type, and transform
its shape and size.
1) If the Character/Paragraph Panel is not in view (above the Layers panel). Go into
the Window menu and select Character.
2) You will need to see rulers to place guidelines down to help position the text. Go into
the View menu and select Rulers.
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3) Position your mouse on top of the horizontal ruler (located at the top of the
window). Hold down the mouse button and drag a guideline down to the image area
(at about 1 inch).
4) Select the Horizontal Type tool in the tools panel. Enter the below in Character
panel:
QuickTime™ and a
decompressor
are needed to see this picture.
5) Click the Text tool on the ruler guide that you placed and type the word (in all caps)
DIGITAL.
6) You will notice that a new layer has been created in the Layers panel titled the same
as the word. Drag this layer down (within the layers panel) so that it is under the
Shadow layer
Making a clipping mask and applying a shadow
Next you’ll fill the type with an image of a circuit board by making a clipping mask.
1) Find and open the circuit_board.tif file. Go into the Window menu and select
Arrange>2-Up Vertical. Both documents should now appear side-by-side. Click on
the circuit board window to activate it.
2) Select the and drag the Background layer from the circuit board document onto
the center of the other image window (the one with the model in it).
3) A new layer should now appear that contains the circuit board image. Close the
original circuit board document.
4) Zoom down so that you can see the entire image area floating within the gray
window area. Select the circuit board layer and then go into the Edit menu and
select Transform>Scale. Hold down the Shift key as you scale the circuit board to
the same width as the text. Then position the circuit board so that it covers the text
completely. When done hit the Return key.
5) Double click on the layer with the circuit board in it and rename it board. Hit the
Return key when done. If the “board” layer is not above the DIGATAL layer, select
drag it so that it is above the DIGITAL layer.
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6) With the board layer still selected, choose Create Clipping Mask from the Layers
panel menu (an down facing arrow located in the upper right hand corner of the
Layers Panel).
7) Click the Add A Layer Style (the fx button at the bottom of the Layers panel), and
then choose Inner Shadow from the pop-up menu. Input the following values:
QuickTime™ and a
decompressor
are needed to see this picture.
Save you work!
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