How to create masks with Magic Wand tools

How to create masks with Magic Wand tools

By Zatni Arbi

JAKARTA (JP): In the world of computer-graphics design, the
mask is as important and essential a tool as it is in the world
of politics.

In CorelPHOTO-PAINT, Adobe Photoshop and other graphics image
editing programs, the masks are perhaps one of the most essential
tools for manipulating images. Take a look at the accompanying
picture. If you have The Jakarta Post's beautiful 1997 wall
calendar, you'll recognize immediately that the picture at the
bottom is of a Sumatran Tiger, skillfully captured by P.J. Leo
for the month of January.

Across the top of this particular picture you'll see a board
painted in yellow and green and you can read The Jakarta Post's
banner -- complete with its subtitle. The portion of the picture
behind the board still shows through the text, as if the text had
been punched through the board. The board is a mask.

For a change, let's explore the possibility of creating this
effect with Photoshop, the de facto standard program for hard-
core professionals in graphics editing. CorelPHOTO-PAINT lovers
don't have to worry because almost all of what we do here can
also be accomplished in CorelPHOTO-PAINT.

The project

To simplify the accounts of the procedure, let me provide you
with step-by-step details of what I did to create the composite
image in the illustration.

First, I used a scanner to scan the image of the Post's
banner. Because the banner extends across the top of the page, I
had to scan it vertically. More importantly, because the image
was basically a black and white one, I scanned it as a black and
white drawing. This eliminated the task of cleaning all the dusts
and ink spot that may have been splattered around the characters.
I chose the .TIF file format before I saved the file, but you can
choose any other popular format for the image.

Next, I opened the file in Photoshop 4.0. I clicked on Image,
and then Rotate Canvas. I rotated it 90 degrees CCW (counter-
clockwise) as necessary. Then I selected the Magic Wand tool from
Photoshop Toolbox. Photoshop had a different approach to
shortcuts. If I chose, I could have just hit the W key once to
select it. In the accompanying picture, the Magic Wand is the
tool underneath the mouse pointer. As I moved the cursor over the
image, its shape changed into a wand that magicians use in their
shows. Then I selected all the areas in the banner that were
white by placing the cursor anywhere outside the black text and
clicking once.

Spots

What the Magic Wand tool does is select pixels of the same
color that are adjacent to each other. We can increase or
decrease the range of colors that the wand is supposed to select.
In Photoshop, the range is between one and 255. A tolerance level
of one will select pixels that have exactly the same color value.
The higher the tolerance level, the wider the range of the colors
of the pixels that get selected.

However, there were spots in the banner that did not get
selected because they were isolated from the main white area by
the black text. In the example, you would find these spots inside
the characters e, a and o. To solve the problem, I just told
Photoshop to look for these insular areas and add them to the
selection mask. To do this, I clicked on Select and then Similar.
Every white pixel in the image was now included in the mask.

We can do a lot of things to the masked area of an image. For
instance, we can change its fill color, punch it out to make it
100 percent transparent, or save it for reuse at a later time. In
this project, I just copied the mask by pressing Ctrl-Ins (or
clicking on Edit, Copy).

My next step was to scan the picture of this animal's handsome
head and opened it in Photoshop. I then pasted the mask that I
had just copied on top of the newly opened image. This created a
new layer on top of the background, and the Layer Palette on the
bottom right-hand corner identified it as Layer 1. Because I had
copied only the white area of the newspaper's banner, the black
text was not copied. It gave an effect as if they were carved out
of the mask.

As usually happens, the mask may be too large or too small.
Rarely will it fit the entire image. The best way to solve this
problem is to go back to the original banner and have Photoshop
resample the image to reduce or enlarge the size as necessary. I
clicked on Image, and Image Size. On the dialog box that
appeared, I increased or decreased the dimensions as needed. What
you must remember is that the ratio between the image width and
height should be maintained. The easiest way to ensure this is to
check the Proportions option.

After I resized the image of the banner and Photoshop finished
resampling it, I had to use the Magic Wand tool once again to
select all the white areas. Then I copied the mask to the
clipboard and pasted it on the picture of the tiger like before.
Usually, the copied mask lands in the center, so I used the Move
tool to drag it to the top of the picture. In Photoshop, we just
have to hit the V letter to select this Move tool.

Once the mask was positioned in the right place, I could turn
the white color into any other color. In this example, I changed
it to a light yellow color. I clicked once on the Foreground
color box at the bottom of Photoshop toolbox. This brought up the
Color Picker dialog box. I chose the color I wanted, and closed
the box. Then I selected the mask once again with the help of
Magic Wand. I then clicked on Edit, and then Fill. On the Fill
dialog box, I made sure that the chosen fill color was also the
Foreground color and the Opacity level was 100 percent. Then I
hit Enter. The mask now was in yellow.

Finishing touch

In Photoshop, we can do more magic tricks with the mask tool.
For example, we can stretch the selection out or shrink it. In
the pictured illustration, I've given the mask a rim. I created
the rim by taking advantage of Photoshop's ability to shrink an
existing selection.

First, I selected the mask once again with the Magic Wand
tool. When I saw the selection marquee around it, I clicked on
Select, Modify and then Contract. Photoshop allows us to expand
or shrink a selection as much as 16 pixels at a time. I chose the
maximum, and the marquee now became smaller than the mask. I
changed the foreground color in the box into green, and then
clicked on Edit and Fill again to fill the shrunk selected area.
The result is as you see in the picture.

Remember that you can copy as many masks as you wish onto a
single image. Each time it will create a new layer. These
individual layers will remain separate until you combine them
with the background. Once you do that, you won't be able to
manipulate the mask in isolation. So, do what you want to do
before you merge the layers together.