Welcome back to our course on PSE 15.
In this section we’re continuing to look at Selection Tools and we’re going to start
to look at the last little set, the last little group here, the group that includes the Quick
Selection Tool that I used earlier on in the course a couple of time.
With the Quick Selection Tool the selection is based on color.
And PSE determines an edge for the selection on the basis of a change of color.
So it should work very well on the sheep in the field because although the coloring on
the sheep varies quite a bit and the coloring of the field varies quite a bit there is always
a clear distinction between them.
Now I’m going to select the sheep.
I’m going to zoom in as usual first.
And when you are using the Quick Selection Tool your basic choice is to use a big brush
which will help you to do the job quickly or a small brush which will help you to do
it accurately.
So what I will often do is use a fairly big brush to begin with.
So I might, for instance, even use say, well what about a 40 pixel brush?
And then having selected the Quick Selection Tool click, move around a little bit, let
PSE make its selections.
And then having done a sort of broad brush selection I may reduce the size and do a little
bit more of the detail work.
Further still.
Let’s get its ears.
Now as I’m doing this PSE by default is adding to my selection.
When as happens here and happens quite often I have some areas selected that I don’t
want selected I’m going to go for the subtract option.
Usually with subtract it’s a good idea to use a small brush so that you can be accurate
about what you’re subtracting.
And I’m going to take away the parts of this selection that are wrong.
Now as I’ve said once or twice already it’s always the case when you’re doing selections
that how good they are depends on how much time you are prepared to or are able to spend
on them.
Now I’ve got one other tiny part of the sheep there that I’d like to deselect.
Okay there’s my sheep selected.
I’m not 100% happy with that selection but as we’ll see in the next section there are
a couple of things that I can do to improve it.
The other color selection tool that I need to introduce you to now is the Magic Wand.
And the Magic Wand works on a completely different basis to the Quick Selection Tool although
it still uses color.
Whereas the Quick Selection Tool detects an edge on the basis of a change of color what
the Magic Wand says is click on a pixel in the image, I can click anywhere, and it will
select pixels within the image that are within a certain tolerance of that setting.
So when I select the Magic Wand Tool the main control I have is a tolerance setting.
And if, for example, I were to click somewhere on the sheep’s back, say there what I get
is a selection of pixels that are within a 32 unit tolerance of the color of the selected
pixel.
Now one very important aspect of this tool is the option in the middle on the right there,
Contiguous.
That’s currently checked.
And that says that these pixels must be contiguous.
They must all be connected to each other.
If I deselect that then it will look for pixels of that color anywhere in the image.
Let me deselect, let me uncheck contiguous, leave the tolerance setting at 32, click within
the sheep’s back once again.
Watch what happens.
I seem to have a pretty good selection there actually.
Let’s click somewhere else with an Add.
Now you see the problem.
Because I’ve got a whole load of pixels in the grass selected.
The light selecting off some of the blades of the grass means that their color is within
the 32 tolerance of the selected color in the sheep.
And in this case the Magic Wand Tool without the contiguous setting is not going to work
because the colors within the ones that I want to select are also present outside my
desired selection.
Let me deselect again, let me recheck contiguous.
With contiguous set it’s probably a reasonable way of doing it.
Although on the basis of what I can see here I’m going to have to click around in the
sheep quite a bit to fully select the sheep.
But if I’m patient it can be a very good way of making a selection.
That’s the Magic Wand Tool.
I’ll see you in the next section.