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Selections, Selections,
Selections! (Part 3)
One thing you have to remember when dealing with selections
is that they are not just for creating masks to draw inside. You
need to select something before you can copy and paste it too. It
is also possible to select something and then apply a filter to
it. Once you have selected it the Photoshop filter will only work
inside your selection.
For example, I have selected the head of the duck
once more. Now any effect I choose to use will only effect where
I have selected.
To prove this, go to the filters section and use one
of its special effects. I'm going to use the glass filter, so go
to: Filter > Distort > Glass..
Bingo! Only the middle will be affected...
SAVING SELECTIONS
If you've spent ten minutes doing a complex selection
you may decide you want to save the darn thing before you loose
it. Or perhaps you just use a selection so often that it would make
life easier if you could load it when you needed. Well, Photoshop
does let you save your selections. Just go to: Select
> Save Selection...
Up will pop this dialouge box. Just choose a nice
name for your selection, I've chosen 'duck head'. Then press OK.
When you want to reload your selection just go to:
Select > Load Selection...
A similar box will appear that lets you choose your
saved selection from the Channel list. It also offers additional
options such as add it to a selection you already have or subtract
from it and so on. Play about with this and see how it works.
| TIP: If you are selecting many parts of
a picture at the same time, then it is usually better to just
copy and paste the parts you are editing onto seperate layers.
A layer can act like a selection and this takes away the pain
of loading and saving selections. I prefer never to save a selection
if I possibly can, its easier to use layers. But this is not
the place to worry about such things! For more details of this
check out my section on layers. |
ANTI-ALIAS
When copying and pasting selections there are a couple
of brilliant options that allow you to control how well the pasted
image blends onto the background its pasted over. These options
are Anti-aliasing and Feathering. Lets see how they work.
I'm gonna use the Polygon Lasso tool to select the
eye of the duck.
But before we select the eye, look up to the options
for the Lasso selection tool; it has a check-box called Anti-aliased.
As you know, computer screens are made up of thousands
of square dots called pixels. Because of this cutting a picture
and pasting it over something tends to give harsh jagged edges.
When anti-aliased is switched on Photoshop will soften these jagged
edges. The illustration below demonstrates this nicely:
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Anti-aliased
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Not Anti-aliased
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You must set the option to anti-alias or not before
you make your selection or it will not apply.
FEATHERING
Feathering is similar to anti-aliasing in that it softens the edges
of a pasted image. Choose the lasso tool again and set the feather
option to something like 5 pixels.
The following illustration shows how the feathered image looks
when pasted feathered and without.
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Non-Feathered
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Feathered by five
pixels
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Feathering can save a hell of a lot of time when it
comes to adding objects to a photo to make it look like they were
there originally. If we didn't have feather then we would have to
go around the whole image by hand blurring it. As a general rule
the larger the picture (the resolution) the higher the amount of
feathering you will need. Small pictures like this duck picture
blur heavily with only a five pixel feather. If the picture were
twice the size you'd need a ten pixel feather to get the same effect.
There are a few other customizable options to controling
how selections select, such as exact sizes, keeping aspect ratio
and so on, but I'll let you play with those yourself. Ready for
the final chapter? Then go to Part
4
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