Selections, Selections, Selections! (Part 1)

After learning basically how to paint with Photoshop there are two vital vital things you must master if you want to get good at it. Namely, Selections and Layers! Learning about selections is the next logical step since you will probably use selections more than any other feature of Photoshop! But what the hell are selections? Selections work a bit simular to the real life masking of pictures. If you have ever done stenciling on walls or paper or have even used masks when airbrushing then you probably already have a rough idea what I mean. But lets illustrate with a simple example. We can make a rectangular selection using the rectangular marquee tool, so select that option by clicking on its icon like this:

Then drag it across the screen to create a rectangle, it should look like this:

The marquee tool flashes like the marquee lights you might find surrounding the entrance of a circus or fairground ride, hence its name. Now choose the brush or airbrush tool and scribble right across the rectangle all the way off the edges. Did you notice that the brush only painted inside the marquee tool like the picture below:

That's what I mean by stenciling. You select a small area of the screen and Photoshop will only affect that small part of the screen. Now, without drawing a new marquee, lets go to: Select > Inverse

Then choose any new colour from the colour palette (I've choosen blue):

And scribble across the picture once again. Our choosing 'Inverse' turned our selection marquee inside out and now Photoshop will only let us draw around the selection instead of inside.

Once you are finished with a selection just click anywhere on the screen with the marquee tool and the selection will dissapear.

ADDING & SUBTRACTING A SELECTION

So now we understand the concept of selections. But what if we wanted to do a couple of selections at the same time, or what if we selected something, and then decided that we didn't want a certain bit of it? Well that is where the Shift and Alt keys come in. I know you want to do everything using icons and the mouse but the only keys we will need to learn for a long time are the Shift, Alt and perhaps the Ctrl key - so don't bitch.

The best way to demonstrate is with another example. Draw another rectangle with the selection marquee like the one I have done in the picture below:

Now hold down the Shift key and drag a new rectangle across the first, like the picture below.

Notice how you have added a selection to the first to create a cross shaped selection. Draw over this and you will get the following picture:

One more time. Lets do our first rectangle like below:

Now drag across it again but this time hold down the Alt key when you do it. Bingo! You have subtracted the shape from the selection. Scribbling over it would look like this:

Okay, I think you get the idea by now. Play around with these controls and see what complex selections you can make with them. There are also a few other marquee tools you can try and they work in exactly the same way.

We have the Elliptical Marquee tool to draw circles and elipses with, and the single row or column marquee tools for drawing pixel thin straight selections.

LASSO SELECTION TOOLS

The rectangular and elliptical selection tools are all fine an dandy for selecting perfect geometric shapes, but what about something more complex? For these objects its usually pretty easy to select them using the Lasso selection tool. These don't need much explaining really. The lasso tool comes in three forms:

The first is the normal lasso tool which lets you literally draw around the shape you want to select. This is actually not all that useful because its almost impossible to get an accurate selection of a complex image. You can of course use the Shift and Alt keys to add and take away bits too but its a pain.

The next much more useful tool is the polygon lasso tool. This one lets you draw one line at a time and reposition the angle of the line like you were tracing it with a series of rubber bands. You just click at the point you'd like to start, move the line to the next point, click again and continue like that. When you are finished just double click and it finishes its selection.

The new additon to the lasso selection tools is the Magnetic Lasso tool. This tries to guess what it is you are trying to select and magnetically snap to the nearest edge of it. Just draw roughly around the image you'd like to select and it will magically snap to the outside of it. This can be very effective for quickly selecting objects on plain coloured backgrounds but becomes very inaccurate for anything else. In our rubber duck example above the magnetic lasso tool works almost like a miracle, but this is the exception rather than the rule!

MOVING SELECTIONS

Moving your selections about the screen is an easy enough task to do. Once you have drawn the selections shape, just click in the middle of it and hold down the left mouse button. You should notice that a small square icon appears below the mouse pointer. This indicates that you can now move that selection. By keeping the mouse button pressed you can drag the selection about the screen. That's all there is to it! Moving selections can be handy especially if you are using the elliptical selection tool and want to position it exactly somewhere or if you need to use the same selection again in a few places like you would a stencil in real life.

Be careful not to confuse moving selections with moving graphic. A selection is not a graphic its a selection. You cannot use the Photoshop "move tool" to move a selection. You must have the selection tool selected and only then can you move your selection. The move tool is a seperate tool designed just for moving graphics.

Okay, that's all for this article. Play about with what you know and try selecting the rubber duck or any of the other pictures that should already be in your Adobe Photoshop samples folder. If you are ready for more then continue on to Part 2 of the selections guide.