Digital Imaging Basics

Frequently you don't want to alter an entire image but rather you want to alter just part of an image.  For example, you might want to remove something from an image...or you might want to correct the lighting on part of an image...or you might want to sharpen something in an image.

To do these manipulations you need to be proficient with the Selection Tools.  The images below are provided for you to practice with.  Copy the images from this article, paste them into your image editing program, then select the item from the images using the appropriate selection tool.

The Rectangular Marquee Tool is used to select either rectangles or squares.  To select a perfect square hold the shift key down while dragging the tool.  Select both the rectangle and the square from the image below and paste them both into a new file.  Save the resulting file into your this weeks folder as .psd file type, including layers, as (yyyymmdd_RectangleSelections

Understand that you have used the Rectangular Marquee Tool because it can Select Squares or Rectangles.

The Elliptical Marquee tool is used for selecting elipses and circles.  To select a perfect circle hold the shift key down while dragging the tool.  Select both the elipse and the circle from the image below and paste them both into a new file.  Save the resulting file into this weeks folder as .psd file type, including layers, as (yyyymmdd_EllipticalSelections.

Understand that you have used the Elliptical Marquee Tool because it can Select Circles or Elipses.

The Polygonal Selection tool is the one that I find most useful.  It takes patience.  Work with high magnification.  Just click, click, click, click, click...until you have closed the circle.  Also note on the tool bar the buttons that allow you to add to existing selections...or to subtract from existing selections.  Select the shape from the image below and paste it into a new file.  Save the resulting file into this weeks folder as .psd file type, including layers, as (yyyymmdd_PolygonalSelections.

You have used the Polygonal Lasso Tool because it can do complex shapes.  This is the selection tool that I use the most.

The Lasso tool is used to draw the selection freehand.  To me this is the most difficult selection tool to use.  Select the shape from the image below and paste it both into a new file.  Save the resulting file into this weeks folder as .psd file type, including layers, as (yyyymmdd_LassoSelections.

You have used the Lasso Tool because the Lasso Tool allows you to simply draw.  Not so easy, though, is it?

The Magnetic Lasso looks for edges with contrast.  The Magnetic Lasso tool will follow an edge.  Note that you can change Width, Edge Contrast, and Frequency.  Experiment with these settings to see how they affect your selection.  Note that this image spans both a black and a white background.  Select the shape from the image below and paste it both into a new file.  Save the resulting file into this weeks folder as .psd file type, including layers, as (yyyymmdd_MagneticSelections.

You have used the Magnetic Lasso Tool because the Magnetic Lasso Tool seeks Edges of Contrast.

The Selection Brush is used just like a paint brush.  Choose your brush shape and size and paint over what you want to select from.  Remember to select the appropriate selection mode (New Selection, Add to Selection, Subtract from Selection, Intersect with Selection).  Select the Lilly flower from the image below and paste it into a new file.  Save the resulting file into this weeks folder as .psd file type, including layers, as (yyyymmdd_BrushSelections.

You have used the Selection Brush Tool because the Selection Brush Tool allows you to make a Selection by simply painting with your brush.

The Magic Wand Selects Color.  Use both the Lily above and the image below for this exersize.  Again from the image above select the Lilly Flower.  And from the image below select first the blue and then select the orange.  In the resulting file you should have three layers of selections...the Lilly flower, the blue selection, and the orange selection.  Save the resulting file into this weeks folder as .psd file type, including layers, as (yyyymmdd_MagicSelections.

You have used the Magic Wand Selection Tool because it allows you to make selections based on color!

As a result of this practice you should have 7 files saved into your class folder, all with layers of selections.  Practice, practice, practice.  Being able to properly select is an asset.