Selecting Things
April 1, 1998
Well, the irony of yesterday was that in the
introduction we said that Photoshop was not really a painting program
yet we spent the rest of the day learning how to paint on our canvas.
Well, that is because you needed to learn the fundamentals
of Photoshop before you could move on to the more exciting features.
Today we will go into some of those more exciting features. In
particular, for the first half of the day we will work with
"Selections".
Selections are areas within the canvas that you
set apart from the rest of the canvas. You can apply special effects
to these areas or other wise modify, copy, cut, flip, move, rotate or
scale them.
It is important
to understand that Photoshop is different from other programs in which
you select things. For example, consider your word processor. Most
likely, when you want to select a word, you double click on that word.
Your word processor knows to select the word because letters are isolate
objects.
Photoshop does not have that
convenience. When you scan in a picture of a face, Photoshop has no
way of discerning between the eyes and the nose on that face. This is
because images are pixel based rather than object oriented. Photoshop
can manipulate those pixels, but it cannot intelligently differentiate
between them in terms of the overall meaning of the picture.
This is a good thing because otherwise, there
would be little use for you. Fortunately, you are needed to decide
which pixels belong to which meaningful part of a picture. For example,
you might want to select a pair of glasses on a face in order to change
the color of the frame. Typical reasons to make selections include:
- Editing a portion of your canvas
- Creating a
mask or
layer
-
Cropping
- Applying
filters
and special effects to portions of your image
To select a portion of your canvas, you will have
to use one of the selection tools that we will discuss later. But all
selection tools do the same basic task, they draw an outline around
some bit of your canvas with a little flashy
marquee
that looks like a dashed line or a row of little
parading ants.
Once you have selected an area, you can manipulate that
area in many cool ways. We will do a lot of manipulation of
selections over today and tomorrow, so it is crucial that we get a
good sense of how to select areas.
Modifying a Selection
We will talk about several tools to make an initial
selection however we should mention here that all selections share
several properties.
For one, any selection can be deselected just by clicking outside
of the selected area or choosing SELECT --> NONE from the main menu
Another such property is that you can edit a selection.
This is a good thing because it would suck to create a detailed
selection only to realize that you missed one small piece. Fortunately,
you can easily add to a selection, remove from a selection or create
selections from intersections of other selections.
To add to a selection, simply hold down the SHIFT
key and use the selection tool to add to the existing outline.
To subtract from a selection, hold down the OPTION or ALT
key (depending on operating system) and use the selection tool to remove
from the existing selection.
To create an intersection selection, simply hold down the ALT
and SHIFT (OPTION-SHIFT) keys and use a selection tool to deselect all
but the overlapping portions of two selections.
You can also hide the selection outline if it is getting in the way of
your concentration by hitting CONTROL-H.
Further, you can inverse the selection, thus selecting
everything that was not selected by your selection by choosing
SELECT --> INVERSE from the main menu.
There are also several built in selection modification tools in the
SELECT menu item. These include Grow, Similar, Border, Smooth, and
Expand/Contract.
These all modify the selection in predefined ways.
Okay, that is a run down of the qualities shared by all
selections. Now let's take a look at the list of tools that you can
use to create selections.
Introduction to Web Design with Adobe Photoshop
Introduction to Web Design with Adobe Photoshop | Table of Contents
The Marquee Tool
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