The
most basic way of making a selection in photoshop is to use one of the
standard shaped marquees. The standard shapes are: elliptical and
rectangular.
There are also two marquees that select either
horizontal or vertical rows that are one pixel wide. These are useful
for drawing one pixel wide lines and creating 'pixel stretch' effects.
See our pixel stretch tutorial here.
In this tutorial we will be selecting the wheel of a car using the marquee tool.
Note
that to remove a selection after it is no longer required (or in order
to make a new selection) use the 'deselect' option on the 'select' menu
[ ctrl - D ] . Also on the 'select' menu you can use the 'inverse'
option to select the inverse of the current selection.
Choose the elliptical marquee from the top left of the toolbar. You may
have to click and hold the tool to bring up the menu of marquee tools.
Once
the elliptical marquee tool is selected draw an oval selection over the
wheel. The easiest way to do this is to hold down the [ Alt ] key after
you have started drawing (this will enable you to begin drawing from
the centre of the wheel rather than from the top left). Another good
tip is to hold down the spacebar while you are holding down the left
mouse button. This will enable you to draw and move the selection at
the same time.
Having
selected the wheel of the car you will want to do something with the
selected area. To copy or move it to a new layer, simply select 'New'
from the 'Layer' menu and choose either 'Layer via copy' [ ctrl - J ]
or 'Layer via cut' [ shift - ctrl - J ]. Thus the selected area of the
image will be copied/cut onto a new layer.
Once you have made a selection you can create another selection that subtracts from the original.
Once
you have selected the wheel you can remove the centre of the wheel from
the selection. Just hold down [ Alt ] while selecting the wheel's
centre.
You can also add areas to the original selection. Hold down [ shift ] while selecting the top ring of the Audi logo.
When
you have finished adding/removing areas from the original selection you
can move the defined area to a new layer or simply shift the selection
to a new area on the same layer. To move the selection to a location on
the same layer just hold down [ ctrl ] while dragging the selected
area. To copy the selection to somewhere on the same layer hold down [
alt ] while dragging the selected area. If you do not hold down [ ctrl
] or [ alt ] you will simply move the location of the selection.
Having
made a selection it is possible to create another selection that
intersects the original by holding down both the [ alt ] and [ shift ]
keys at the same time while drawing the second selection.
Start
by selecting the wheel with the elliptical marquee tool. Then hold down
the [ alt ] and [ shift ] keys together while drawing a rectangular
marquee ( you will need to switch to the rectangular marquee tool) that
intersects the original selection. Note: intersection is the default
behaviour after a selection has been made, thus holding down [ alt ]
and [ shift ] together is optional.
Draw the rectangular selection so that it cuts off the top and bottom of the oval.
Final
Tips: Selections can be nudged into position rather than dragged. Thus
giving you more positioning control. Nudge selections one pixel at a
time using the arrow keys. Hold down [ shift ] to move 10 pixels at a
time.
If
you have trouble remembering the keyboard shortcuts for adding,
subtracting and intersecting selections you can use the buttons on the
above toolbar.
If you hold down the [ shift ]
key AFTER you click and drag using the marquee tools (rectangular or
elliptical) then they will form perfect squares and perfect circles no
matter how you drag the mouse.
The way to make the rectangular marquee most useful is to use a 'free
transform'. Simply draw a rectangular marquee. Then select 'transform
selection' from the 'select' menu. Then go to a corner of the
selection, hold down the [ ctrl ] key and drag the corner into place.
Free
transformation can also be used with elliptical marquee tool to make
fine adjustments and thus find a perfect fit between the selection and
the image.