Photoshop: What is a selection?

What is a Photoshop selection?Many of my Adobe Photoshop beginner students ask this question. I usually start by describing a selection as a mask for applying an effect or a method for isolating a region of an image for copying, moving or deleting. The truth is, they have many uses and selections play a pivotal role in any project, great or small. You simply can’t get by in Adobe Photoshop without learning at least the basic of these busy little things.

Selection tools

Marquee toolsMarquee tools

A collection of predefined selection shapes, comprising of rectangular, elliptical, single row and single column. To create a square or circle using the rectangular and elliptical marquee tools, hold down the shift keys whilst clicking and dragging.

  • Rectangular Marquee (M): Left click at your start point and drag mouse to create Rectangle.
  • Elliptical Marquee (M): Left click at your start point and drag mouse to create Ellipse.
  • Single Column Marquee (M): Left click at your start point and drag mouse to create Single Column.
  • Single Row Marquee (M): Left click at your start point and drag mouse to create Single Row.

Lasso toolsLasso tools

The Lasso tools allow you to make free-form selections around irregular objects within images. For example, using the Polygonal Lasso tool, you can create a complex mask around a photographic element for copying and pasting or colour and tone adjustment.

  • Lasso (L): Click and carefully drag your mouse around the perimeter of your image. As soon as you release the mouse button, the selection will automatically close to complete. If you hold down the ALT key whilst defining, the Lasso tool becomes the Polygonal Lasso tool for as long as the key is held.
  • Polygonal Lasso (L): Click and plot points around your shape. The DELETE key can be used to ‘unpick’ points before a selection is completed. To complete, let your mouse hover over your start point and left click to complete. You can also double click to close selection, hitting the ENTER key will have the same effect. The ESCAPE key will cancel.
  • Magnetic Lasso (L): Left click at your start point (somewhere very close to an edge) and either click and drag or just let your cursor move around your shape. Anchor points will automatically appear along defined edges.  The DELETE key can be used to ‘unpick’ points or anchors before a selection is completed. Double click to close. ENTER key will have the same effect.

Magic Wand & Quick Selection Tool

Magic Wand Tool & Quick Selection Tool

A quick and simple method for creating a selection. These tools offer a one click solution but take away much of the control found in the Lasso tool-set. Will work with some image elements, but not all.

  • Magic Wand (W): Click on the area of continuous tone or colour to make a selection. I tend to depend heavily on the options bar with this tool for extra control.
  • Quick Selection (W): Paint around your object and it will automatically select areas within with the same tone, colour or texture. This tool goes a lot further than the Magic Wand tool

Recommended tools

Out of all of the various selection methods that Photoshop has to offer, I would say by far the best all rounder is the Polygonal Lasso tool. This is because of the level of control it gives the user. Being able to incrementally plot around an object allows you to take your time to perfect a selection.

Building & modifying selections with the Options Bar

Selections via the Options BarSometimes you’ll have to amend your selection. May be add a little bit here, and subtract a bit there without having to start from scratch. If you look to your contextual Options Bar, you’ll find a little row of buttons to help you out here. The current mode will be the indented or highlight button.

  • New selection
  • Add to selection
  • Subtract from selection
  • Intersect with selection

Adobe Photoshop will remember your last choice of mode for each individual selection tool, so don’t forget to check this before making changes.

Hiding & showing your selections

Those ‘marching ants’ around your selection can visually clutter up the screen and distract you form observing the finer points of your image. I find this especially distracting when then altering the light or colour. By pressing CTRL+H you can toggle between a hide and show.

Feathering

To soften the edge of your selection press CTRL+ALT+D to bring up the Feather  dialogue box. You can also find this in (menu)->Select->Feather. The Feathering radius determines the softness. From the centre of the edge of your selection, a gradient of opaque to transparent is created at the given radius in pixels. You can input a feather radius via the Options bar, but I would strongly advise against this as you will be unable to UNDO the feather, should it be wrong.

Inverse selection

You’ve made a selection and applied all of the changes within it, but now you would like to select everything other than your selection.  CTRL+SHIFT+I or  (menu)->Select->Inverse, will invert it.

Smooth, expand or contract selection

These can be found under (menu)->Select->Modify. Smooth the edges without softening with feather, or ‘Expand’ or ‘Contract’ your selection pixel by pixel.

Similar

Similar can be found under the  (menu)->Select->Similar. This feature allows you select other pixels throughout the image with a similar colour tolerance to that within your current selection.

Saving & Loading your selections

Save your carefully created mask for future use. This can easily be done by calling up the ‘Save selection’ dialogue box. You will find this under (menu)->Select->Save selection. Choose a name and click on ‘OK’. Choose  (menu)->Select->Load selection to load your previously saved mask. Click on the Channel drop-down menu in order to choose you saved entry. Saved selections can be managed from the Channels floating palette.

Further reading

Feather via the Option Bar

Choosing the best selection tool

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