Fireworks
The Fireworks Fuzzy Edge Quick Knockout Mask
Keep your edges in line
Nov. 17, 2003 12:00 AM
Masking fuzzy or irregular
edges is typically a slow,
painstaking procedure of
hand selection with the Polygon Lasso
tool, or if you prefer a vector mask, the
Pen tool. Plugins that automate the
process (e.g., Extensis Mask Pro, Corel
Knock Out) are expensive for one-trick
ponies. And shame on Extensis and Corel
- they haven't been made available for
Fireworks. This article will teach you to
quickly mask objects with irregular edges
using the new Fireworks MX 2004
Replace Color tool, a simple Alpha masking
technique, and some sneaky edgerefining
tricks.
I'm going to use a gorgeous flower
image (see Image I), photographed by
Daniel Reyes of Sydney, Australia, to
demonstrate the technique. (If you'd like
to download a copy and follow along, go
to www.playingwithfire.com/flower.zip.)
Unzip the image file, and open it in
Fireworks MX 2004.
A Word About Masks
In Fireworks you can apply two
kinds of masks: clipping masks and
Alpha masks. Clipping masks work like
cookie cutters, clipping the underlying
objects to the shape of the mask. If
you've ever pasted one object inside
another in Fireworks, you've used a clipping
mask.
Alpha masks affect the visibility of underlying
objects. They are made with grayscale
gradients that tell Fireworks how much to
blend the underlying pixels with the pixels of
the background it sits on. If you want to fade
one image into another or make part of an
image invisible, you use an alpha mask.
Preparing the Alpha
(?) Mask
Since the mask we'll create is going to
work like a cookie cutter, it could be
called a clipping mask. But since our
mask will fade part of the image, it will
work as an Alpha mask. Instead of concerning
ourselves with these technical
details, let's just do it.
Step 1
- Select the image by clicking on it and
choose Edit _ Clone.
- Open the Layers panel and select the
lower, flower-image thumbnail.
- Hide the selected image by clicking on
the hide object icon (the eyeball).
There is good contrast between the
flower and the background of the image
in Daniel's photo. That means it can do
most of the work of preparing the Alpha
mask by adjusting the contrast.
- Click on the image to select it.
- Choose Filters _ Adjust Color _
Brightness/Contrast. The
Brightness/Contrast dialog box will
open (see Image II).
- Move the Brightness slider all the way
to the left, to the -100 position.
- Move the Contrast slider all the way to
the right, to the 100 position. This
reduces the number of colors in the
image to four or five, and makes the
next step, replacing colors, go very
quickly (see Image III).
Step 2
Select the Replace Color tool. Set the
properties for the Replace Color tool in
the Property inspector, as follows:
Size: 70
Shape: Round
Tolerance: 50
Strength: 200
To set the Change property:
- Click in the Change fill color box in the
Property inspector to open a swatches
pop-up.
- Use the built-in color picker of the
swatches pop-up to select the green
color adjacent to the upper left flower
petals.
To select the color you want to
change the green to:
- Click in the To Fill color box in the
Property inspector.
- Use the built-in color picker to select
the black swatch in the swatches
popup (see Image IV)
- Click and drag the Color Replacement
brush over the image background to
replace all of the green pixels with
black
Let's select a new color to change.
- Click in the Change fill color box to
open the swatches pop-up.
- Use the built-in color picker of the
swatches pop-up to select the aqua
color near the top right of the image.
Leave the remaining settings as they
are.
- Sweep quickly over the image with
the Replace Color brush to change
all the aqua pixels to black.
We need to remove the white and
yellow pixels in the background next.
It's necessary to exercise some care
when replacing these pixels because
there are white and yellow pixels at the
edges of the flower that we need to
preserve. Enlarging the image will
make this a snap.
- Click in the Set Magnification box at
the bottom of the document window.
Choose 300% from the pop-up
menu (see Image V). Alternatively,
select the Zoom tool from the bottom
of the Tools panel and click a
couple of times in the area you want
to work on first.
- Make the Change color either white
or yellow.
- Reduce the size of the Replace Color
brush to 18 or less.
- Replace the white or yellow pixels in
the background with black, being
careful not to go over the outside
edges of the flower petals.
When you've finished replacing the
color you selected, switch the Change
color and carefully remove the
unwanted pixels of the other color.
There are some scattered blue and
pink pixels left in the background. Use
the Replace Color tool to change them
to black, or paint over them with the
Paint Brush tool.
Step 3
In this step we'll prepare the flower
portion of the image for our Alpha
mask.
- Click in the Change fill color box on
the property inspector to open the
swatches pop-up.
- Use the swatches pop-up color picker
to select a white area inside the
flower.
- Click in the To color box in the
Property inspector and use the
swatches pop-up color picker to
select the red color of the flower.
- Sweep over the flower with the
Replace color tool to change the
remaining white pixels to red.
- Replace the white Change color with
the yellow from the image.
- Sweep over the flower with the
Replace Color tool to replace all the
yellow pixels with red.
- Replace any pink pixels with red.
- Replace the black pixels inside the
flower with red.
The entire image has quickly been
reduced to black and red. Next, we
want to change it to black and white.
- Set the Change color to the red from
the image.
- Replace the To color with white.
- Set the Tolerance to 100.
- Brush over the red pixels in the
image with the Replace color brush
to change them to white (see Image
VI).
Our Alpha mask is nearly finished.
The last step before masking the image
is feathering the edges of the mask.
Step 4
If we use the Alpha mask as it is, the
edges of the flower petals might look
jagged. To soften them, we'll select the
black background and pour a feathered
fill into the selections.
- Click on the Magic Wand tool.
- Set the Tolerance for the Magic
Wand tool to 33 in the Property
inspector.
- Set the Edge property for the Magic
Wand to Feather, and the amount of
feather to 1 (see Image VII).
- Press Shift and select the three black
sections of background around the
flower.
We'll fill the selections with the
Paint bucket tool.
- Click in the Fill Color box on the
Tools panel.
- Select a black swatch to set the fill
color to black.
Note: If you see a color in the Stroke
Color box in the Tools panel, click on it
and change the color property to
None.
- Click on the Paint Bucket tool to
select it.
- Click three or four times in each of
the areas you selected with the
Magic Wand.
- Choose Select _ Deselect to turn off
the marquees (marching ants).
The edges of the flower shape are
now anti-aliased to the black background
and our Alpha mask is complete.
Applying the Alpha Mask
Before applying the mask we need to
unhide the original image. In the Layers
panel, make the hidden image visible
again by clicking on its thumbnail. Now
for the fun part!
- Press Shift and select both the Alpha
mask thumbnail and the original
image thumbnail.
- Choose Modify _ Mask _ Group as
mask (see Image VII).
Shazam!
The black background disappears,
instantly converting the flower to an
image object floating on a transparent
canvas (see Image IX). That is just way
too cool. If you'd like to perform this
trick again, choose Modify _ Ungroup.
Shift + select the two bitmaps again
and choose Modify _ Mask _ Group as
mask.
The edges of the knocked-out flower
may still look a bit rough. In the next
section I'll show you how to smooth
them by applying some Fireworks Live
Effects.
Refining the Edges
The edges shouldn't need much
touching up, particularly since you would
reduce the dimensions of an image this
size before using it on a Web page. If you
feel the edges need smoothing all the
way around the flower, then with the
masked image still selected
- Click on the Add Effects button [+] on
the Property inspector.
- Choose Shadow & Glow _ Glow.
- Click in the color box of the Glow
dialog and select a medium color
from the edges of the flower petals
(see Image X). If you're not satisfied
with the color you can change it
later.
- Click on the down arrow next to the
Glow width text box and use the slider
to change the width to 1.
- Set the Glow softness to 1 by means of
its slider, or by simply typing a new
number into the text box.
If just one side of the image edge
needs smoothing, choose the Drop
Shadow Live Effect.
- Click on the Add Effects button [+] on
the Property inspector.
- Choose Shadow & Glow _ Drop
Shadow.
- Click in the color box of the Drop
Shadow dialog and select a medium
color from the edges of the flower
petals.
- Adjust the Shadow width to 1.
- Set the Shadow softness to 1.
- Click on the down arrow next to the
angle text box and use the built-in dial
to rotate the shadow to the correct
position.
Other live effects you can use to
adjust the edges of your extracted image
are Inner Glow and Inner Shadow.
Finishing Up
To check the quality of our work, let's
add a background. Select the Vector
Rectangle tool and drag out a white rectangle
the same size as the canvas. With
the rectangle still selected:
- Click on the down arrow of the Fill
type selector and choose Gradient.
- Choose the Waves gradient from the
gradient pop-up palette (see Image
XI).
- Click in the Fill Color box to open the
Gradient editor.
- Click on the black chip and change its
color to medium gray or blue.
To send the gradient-filled rectangle
behind the image, choose Modify _
Arrange _ Send to Back (see Image XII).
That's it! Congratulations on a job
well done. I hope you'll make much use
of the techniques you learned while following
this exercise.
About Linda RathgeberLinda Rathgeber is a writer, Web developer, and Team Macromedia member who coaches newcomers using Macromedia Dreamweaver and Fireworks. Her graphics work has been featured by the independent film company King Pictures, in book ads for author Bill Stott, in the Fireworks 4 and Fireworks MX sample files, and on the companion CD-ROMs of Joseph Lowery's Fireworks Bibles. Visit Linda at www.playingwithfire.com.