Simple masks are easy to make.
Complex masks, on the other hand, can sometimes take hours to create,
so saving a mask becomes almost as important as saving the image.
Saving a Mask
All masks created in Corel PHOTO-PAINT can be saved and reloaded.
This ability to save masks is essential because:
1) only one regular mask can exist on an image at a time: so to use
multiple masks during a project, it becomes necessary to store them;
(using Additive mode, you can create several mask outlines, but
the result will be one regular mask)
2) if you spent several hours creating a mask, it is essential to
have a copy;
3) a mask is a great way to copy the same size image are out of several
different images.
Saving a Mask with the Image
There are two ways that a mask can be saved:
it can be saved to disk or saved with an image in a temporary storage
called a channel.
An image containing a regular mask, that is saved in Corel PHOTO-PAINT
format, will have its mask saved with the image automatically.
In addition to Corel PHOTO-PAINT format, masks can be saved in TIFF
(.tif) formats.
They are also saved as alpha channel information when an image is
saved as an Adobe Photoshop (.psd) image.
Saving masks to
disk is just like saving image files.
Assuming you have a mask you want to save, choose Mask/Save and the
drop-down menu shown above opens:
choose Save Mask to Disk and, when prompted, select a drive and folder
from the dialog box, name the mask file and select the file type
(CPT
is strongly recommended).
note: do not use a unique extension
such as .msk for the mask: this three-character extension is used
by Corel PHOTO-PAINT and other applications to determine the correct
import filter to use. Although the mask can be saved in any bitmap
format (PCX, TIFF, BMP, and so on), it is recommended to save masks
in Corel PHOTO-PAINTs native CPT format.
The ability to save a mask apart from the image allows a mask created
in one image to be loaded and applied to other images for special
effects or accurate placement of objects.
How a different application uses the saved mask information depends
on the application. For example, the mask information in a .tif or
.tga file is interpreted by Photoshop as an alpha channel.
Loading a Mask
The Load Mask function allows a wide variety of image file formats
to be loaded as masks.
Any image file can be used for a mask: using photographs or other
non-mask files may give unpredictable, although not necessarily undesirable,
results. A non-mask file is any image file that was not created using
the mask tools in Corel PHOTO-PAINT.
When loading a mask, it is important to be aware that Corel PHOTO-PAINT
will resize the mask to fit the image!
note: if you have
several images open on your screen, make sure that the one you want
to load the mask into is active: if you load the mask into another
image, the mask may replace any existing mask in that image, depending
on the mask mode.
Loading a mask into an image involves the following procedure:
1. Select the image to which the mask being loaded will be applied.
2. Choose Mask/Load/Load from Disk: the Load a Mask from Disk dialog
box opens.
3. Select the file to be used for a mask: while any image can be used,
the mask will become a black-and-white or grayscale image.
4. Click the Open button and a thumbnail of the mask you are loading
will appear on the cursor, as shown next. The mask being loaded in
this illustration is a mask of the word "mas".At this point
you have two options:
a) click the cursor anywhere on the image and the mask will be applied
to the entire image, as shown (below left).
b) click and drag a rectangle and the mask will be resized to the
shape you dragged: center figure shows a mask that was made much smaller
and in the right figure, the mask was made larger (and a little bit
lower) than the original: this action can cause some deterioration
of the edges. |
| original mask |
mask resized smaller |
mask enlarged |
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Saving a Mask As an Alpha Channel
Since only one mask can be active in an image, each new mask you create
replaces the current mask.
When creating special effects, it is possible to use three or more
masks.
While we could save each of these to disk, as previously described,
we also have the option to save the current mask to an alpha channel
in the image so that it can be reused.
When you save an image to a file format that supports mask information,
such as Corel PHOTO-PAINT (.cpt) or TIFF bitmap (.tif), the current
mask and all alpha channels are saved with the image.
You can also save the current mask or an alpha channel to disk as
a separate file.
Saving a mask or an alpha channel lets you use masks in other images.
This is especially useful if you want to save an image to a file format
that doesn't support mask information, but you want to keep copies
of the masks used to edit that image.
Saving a mask to an alpha channel is also very easy: choose Mask/Save/Save
As Channel.
This opens the preceding dialog box that asks you to name the channel
in which the mask will be stored, as shown (default: Alpha1, Alpha2,...).
The mask is now safely stored as an alpha channel. Managing
Masks and Channels
The alpha channel can hold a large number of masks.
To load a mask from the alpha channel, choose Mask/Load and the drop-down
menu that appears, shown next, displays all of the alpha channels
that have currently been assigned.
The Channel docker
the Channel docker (shown right) has many masks stored as alpha channels:
one of those is also the current mask.
Whenever you click a channel, its contents appear in the current image
window.
note: you cannot delete any of the color channels
using the Delete icon.
The size of the thumbnails in the docker is controlled by the flyout
option in the upper-right corner of the docker.
Exploring Channels
The top entries are the composite (RGB, in the example) and, below,
the individual channels.
Whenever a mask is created, the Current Mask appears below the individual
color channels. Although an image can have only one mask at a time,
you can store many different masks with an image in the form of channels.
You can create a new channel without a mask by clicking the Create
New Channel button at the bottom of the docker.
Removing a Mask
Click the Remove Mask button located on the Mask/Remove (CTRL+R).
A mask must exist on the active image for the mask button in the toolbar
to be available.
Use the DEL key: a mask may also be removed with the DEL key if the
mask is selected as indicated by the control handles (the mask
is selected whenever the Mask Transform tool is selected).
If the mask is not selected, the DEL key will clear the contents of
the mask. Therefore, use the DEL key with caution.
Inverting a Mask
One of the more useful mask functions is the Invert Mask command (CTRL-SHIFT+I).
When a mask is created, the area inside the mask can be modified while
the area outside the mask is protected.The Invert Mask command reverses
the mask so that the area that was inside the mask now becomes protected
and the area outside can be modified.
The Invert Mask command can be accessed through the Mask menu on the
Mask/Object toolbar by clicking the Invert Mask button or with the
keyboard combination CTRL-SHIFT+I.
note: some masks are so
complex that it is difficult to determine what part of the image lies
inside or outside of the mask. A quick way to check is to select the
Mask Overlay button on the Mask/Object toolbar. Only the tinted area
(red, by default) is protected. The Mask Overlay is a display function
and does not affect the operation of PHOTO-PAINT.
Select All
To mask the entire image, click the Select All button from the Mask/Object
toolbar or choose the Select All command in the Mask menu.
You can select the entire image by double-clicking any of the Mask
selection tools in the Toolbox except the Mask Brush tool.
The mask will encompass the entire image inside of the image window.
If the image is only partially visible because you have zoomed into
an area, the entire image is still masked.
Manipulating
Masks
After a mask has been created, we often need to modify it.
Corel has provided several mask manipulation tools to help us do this.
Feather Mask
Technically speaking, feathering a mask changes the transparency of
the pixels located near the mask boundary: any effect or command applied
to the selection fades gradually as you get near the protected area.
Feathering can be applied to a mask during or after its creation.
It is particularly useful if you want to apply an effect to the masked
area but not the surrounding area: feathering a mask makes the transition
between the two areas gradual and, therefore, less noticeable.
Photo, below, shows an example of an object created from a photograph
using a nonfeathered mask and one from a feathered mask (right). |
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On the property bar, we can set only the inside feather width (below)
Whether you select Mask/Shape/Feather from the Mask menu, a dialog
box opens enabling you to set the direction, amount and type of feathering
to be applied to the current mask.
The Width setting determines how wide a feather to apply
to the mask edge.
We also have a choice of two different Edges: Linear and
Curved. |
| inside |
middle |
outside |
average |
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Above, the Feather Mask command was applied to identical
masks.
The masked area was filled with 100 percent black fill and zoomed
to 300 percent.
The Shape Category Mask Commands
Some of the other mask commands you may have occasion to work with
are located in the Shape category of the Mask menu: Border, Remove
Holes, Smooth, Threshold, Expand, and Reduce.
Border
The Border command removes a portion of an existing mask to a border
according to the setting in the Border dialog box.
It offers the option of three different Edges settings: Hard, Medium,
and Soft. Borders only move outward from the mask regardless of the
Mask Mode setting.
Be careful when applying this command to circles: it tends to degrade
the general shape of the circle.
In the next illustration, the mask created from a square has a 20
pixels border applied, creating a diffuse glow: the preview feature
of the mask is shown in left image.
note: for a creative effect,
try applying the Border command to a square or rectangular mask multiple
times (right). |
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Remove Holes
Remove Holes is supposed to remove those nasty little mask fragments
that tend to be left when using the color-sensitive masks.
As a result, when the conditions of the mask and image are suitable,
it works great.
It has no adjustable settings.
Smooth
The Smooth command creates a more fluid mask boundary by smoothing
out sharp bends (jaggies) in the mask that occur especially when creating
color-sensitive masks.
Some pixels that are not in the selection before smoothing will become
part of the selection after smoothing and some pixels that are currently
in the selection will no longer be included in it.
The Smooth command, like the Remove Holes command, can sometimes eliminate
entire portions of a mask.
The amount of smoothing this command does is dependent upon the Radius
setting you enter in the dialog box.
Large values tend to completely change the shape of the mask.
Below you can see an example:
(a): the original ragged mask edge;
(b): smooth at 10;
(c): smooth at 30;
(d): smooth at 50;
in c and d, the Radius setting of the Smooth mask command has significantly
altered the shape of the mask. |
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Threshold
The Threshold command is the opposite of the Smooth command.
When you have a mask with an indefinite edge, as with a feathered
mask, this command makes it into a binary (black-and-white) mask by
applying a Threshold function to it.
It allows to make the edges of masks more distinct.
The only setting, Level (1-255), determines which grayscale values
in the mask become white (below the Level setting) and which become
black (above the Level setting).
Expand and Reduce
Use them to make masks larger or smaller. Like the Border command,
these commands tend to degrade shapes with large values or multiple
applications. |
| threshold: level 150 |
expand: 7 pixels |
reduce: 7 pixels |
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The Color Mask
Most of the color-sensitive masks could only include colors that were
connected to the original sampled color. The Color mask, like the
Similar command, selects pixels by their color content, regardless
of the position of the selected pixels in relation to the original
sample point.  Selecting Color Mask, located in the Mask menu, opens the dialog box
shown below. The dialog box is quite simple to use: use the eyedropper
to select colors in the image that you want masked.
If you don't like the result of one of the color selections, remove
the checkmark from its box.
Use the Preview (it looks like an eye) option to determine how successful
the color selection process has been and click the OK button.
1) the Color mask uses a dialog box: so you must complete the selection
of the mask and apply the mask before you can do any other operation.
2) the Color mask command does not create a Color mask: it creates
regular masks.
When you save a Color mask, you are saving the settings of the Color
Mask dialog box.
3) Preview of the mask made by the Color Mask tool is done on the
actual image.
Selecting individual colors in a complex image can take time, even
with the Color mask.
The first step is to mask all of the colours we have to change:
1) Select Mask/Color Mask to open the dialog box;
Click the Reset button to clear any previous settings;
2) Click the Eyedropper button and place the cursor in the image and
it will become an eyedropper; Click the image at desired colour portions
of the image;
3) Click the Preview button and the image in the Preview shows masked
(protected) areas in a red tint. Click the OK button. |
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4) Select Mask/Mask Overlay.
Select the Mask brush and change the mode to Subtractive by clicking
the minus button on the property bar (if you wrong, change mode to
Additive).
Now paint all of the areas outside of boundaries.
note: technically,
you could use the mask marquee to find the areas to remove, but it
is much better to use Mask Overlay.
When you have finished with the mask, turn off the mask overlay.
5) Here to change the color, Image/Adjust/Hue-Saturation-Lightness
has been chosen.
Edit the Hue setting to +100 and click OK. |
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Additional Information About the Color Mask
There are other controls in the Color mask dialog box that deserve
some explanation.
Across the top are the four Mask Mode buttons and the Invert Mask
button:
the Mask Mode buttons control how the mask you make with the Color
mask tool reacts to an existing mask;
the Invert mask is a feature that allows you to either protect or
select the sampled colors.
When you click the Reset button in the Color Mask dialog box, it resets
the mask mode to whichever mask mode PHOTO-PAINT is in.
Clicking the "More »" button on the Color Mask dialog
box opens the rest of the dialog box, containing a few additional
settings that modify how this mask tool operates.
From the expanded dialog box, you can determine what criteria the
Color mask uses to select its color: you can use HSB instead of Normal
mode.
For most applications, the Normal setting (default) will do the job.
HSB uses a combination of hue, saturation and brightness to make its
selection of colors.
You can also select to use the HSB components individually to determine
which colors are selected. The Threshold settings act just like the
Threshold filter: they use the value of the Threshold slider to cause
the created mask to move toward either white or black.
Click the flyout option arrow to get even more options:
you can save all of the settings as a Color mask file: this file can
be loaded into the Color mask and used at a later time;
the Color mask can also be saved to an alpha channel through this
option: when saved as an alpha channel, it is a grayscale image that
can be used as a mask but cannot be loaded as a Color mask file later
on;
set Tolerance Default sets the default tolerance value that is used
when colors are sampled: the default setting for the Color Mask tool
creates a mask in Sampled, Colors mode: in this mode, everything that
is not selected is protected;
if you right-click one of the color selections, the Delete Color and
Edit Color options become available: choosing Edit Color opens the
Color Palette dialog box from which you can specify a color to select:
if, for example, you wanted to select every place in the image that
the color PANTONE CV742 was used, this is where you would make the
selection;
at the top of the Color mask (next to the Eyedropper icon) is a large
list of preset settings that allows you to quickly select a type or
range of colors or shades;
I strongly recommend that you use
Sampled Colors;.
the Preview button changes the image so that you can see the parts
of the image that are currently masked; there are several options
available for viewing the Color mask:
the default setting is Overlay, which places a tint over
the masked area: the advantage is that you can see the mask in relation
to the image;
another way to preview the mask is the Grayscale setting:
in which you cannot see the image, just the grayscale image that is
the mask;
the Black Matte or White Matte preview options display
protected areas covered by a black-tinted transparent sheet or by
a white-tinted transparent sheet, Marquee displays a dotted
line around the editable area, just like the mask marquee normally
displayed for masks.
Using the Color Mask More Productively
If you are attempting to mask a narrow range of colors, like the blue
in a sky, use multiple samples or take a single sample and increase
the Numerical setting for it; many times when selecting a color or
range of colors, you end up with parts of the image selected that
you didn't want selected: rather than waste time trying to balance
the color and Numerical settings to get the "perfect" mask,
use the Color mask dialog box to create most of the selection and
then use the mask tools to fine tune the mask to its final shape;
when changing the Numerical value, the Preview window won't reflect
the changes until you press the Enter key or click another color. |
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Paths
Paths are line and curve segments connected by square endpoints called
nodes.
A mask is created from a bitmap image;
a path is a vector drawing that exists on a layer above the
image and is independent of the image resolution;
a closed path completely encloses an area, as a mask would, an open
path has start and end nodes that are not connected: this is something
that a mask cannot do.
The advantage of the path over the mask is, in a word, precision.
A path, being a vector image, can be precisely edited;
a mask, being a bitmap image, is adjusted by adding or subtracting
from it with a Brush tool or something similar.
With a path, you have full Bezier-level control over the points and
nodes, just as you have in CorelDRAW.
When you need to make accurate masks, you will want to create
a path using the Path Node Edit tool.
New paths can be created using the Path Node Edit tool or existing
masks can be converted to paths: when the path is exactly the shape
you want, you can save the path or convert it to a mask, or both;
a mask can be converted to a path, edited as a path and converted
back to a mask.
If you export a mask as a part of an encapsulated PostScript (EPS)
image, the mask is converted to a path. |
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Stroke Mask/Path Command
This command is used to automatically apply brush strokes along a
path defined by either a mask or a path. You can use it to apply many
of the brushes.
Operation of this puppy is simple: select the brush/tool you want
to apply;
make any changes to the size or shape of the nib, and then click the
appropriate button on the property bar, this opens the dialog box
where you can select a stroke on, inside or outside the mask; to make
the Stroke Mask or Stroke Path options available, there must be a
mask or path on the image and one of the following tools must be selected:
the Paint tool, the Effect tool, the Color Replacer tool, the Eraser
tool or the Image Sprayer tool. |
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