Photoshop
Selections
Review Answers
Answers
- Describe the purpose of a selection.
A selection isolates a portion of an image that you want to edit and protects the rest of the image from changes. - Identify all the selection tools and briefly describe how they function.
Marquee tool - draws a rectangular or square selection.
Elliptical Marquee tool - draws an oval or circular selection.
Single Row Marquee tool - draws a 1-pixel high row across the width of the image.
Single Column Marquee tool - draws a 1-pixel wide column across the height of the image.
Lasso tool - draws a freehand selection.
Polygonal Lasso tool - draws straight lines between points to make selection.
Magnetic Lasso tool - draws a selection that snaps to a contrast in colours.
Pen tool - draws a vector-based path selection.
Magic Wand tool - makes a selection based on the target pixel's colour and that of the pixels around it. - What are the benefits of creating a selection based on a path?
A path selection is automatically saved with your image file, it is scalable (up or down in size) and you can add, delete or modify points in the path. - Describe how to add to, remove from and move a selection.
You can add to a selection by holding down the Shift key or by clicking on the second box in the Tool Options panel and then creating another selection. Holding down the Alt (Option) key or clicking on the third box in the Tool Options panel and then creating another selection will remove from your selection. To move a selection click on a selection tool and click and drag within your active selection. Alternately, you can use the directional arrow keys to nudge a selection as long as the Move tool isn't the active tool. - What does adding a Feather radius to your selection do?
It applies a smooth or blended edge all around your selection or image. -
How do you create a perfectly circular selection?
By holding down the Shift key while dragging with the Elliptical Marquee tool. -
How would you apply feathering before a selection is drawn? After?
Before a selection is made, set a feathering amount in the Tool Options bar. After a selection has been made, you can use the Selection > Feather command. -
Can anti-aliasing be applied to a selection after it has been created?
No. -
When using the Magic Wand tool, what adjustment would you make to include a greater number of pixels in your selection?
You can increase the Tolerance value to select a larger area of contiguous pixels. You would also be correct in saying that disabling the Contiguous option will allow more pixels to be selected. -
When drawing a path with the Pen tool, how do you complete a closed path? How do you complete an open path?
To complete a closed path, click once on the starting point with the Pen tool. To complete an open path either select another tool in the Toolbox or click away from the path in the image with the Pen tool. -
What is the purpose of direction lines in a path?
Direction lines are present when curve points are created. Manipulating direction lines by dragging on their end points will alter the size and slope of the adjacent curves. -
How is a path converted to a selection?
Choose Make Selection from the Paths panel menu, set the options for your selection in the Make Selection dialog and then click OK. -
Name four criteria on which you can make selections using the Colour Range dialog.
Sampled colours (using an Eyedropper), preset colours, highlights/midtones/shadows, or out of gamut colours. -
Name the six ways that a selection can be transformed by using the Transform Selection command.
Horizontal scale, vertical scale, scale (horizontal and vertical together), rotate, skew, perspective. -
How would you scale a selection while retaining its width-to-height ratio?
Hold the Shift key while dragging a corner handle of the Transform bounding box. -
Holding down the Shift key while rotating the Transform bounding box will have what effect?
The bounding box will snap at each 15o angle during the rotation. -
What is the difference between the Grow and Similar commands?
Grow will add adjacent pixels to a selection while Similar will add both adjacent and non-adjacent pixels.
Bonus Answers
- If you had a photographic image of a multi-coloured flower on a solid white background, what do you think the most efficient method would be to make a selection of the flower without including the background?
Set the Magic Wand tool to a Tolerance of 0 and non-contiguous. Click on the white background and invert the selection. -
Let's say you have an image that is 300x300 and you want to draw a square selection that is 100x100 and have it perfectly centred in the document. How would you go about it?
Set the Rectangular Marquee's Style option to Fixed Size and enter 100 in both the Width and Height fields. Then click at the X and Y coordinates of 100 and 100 to create the marquee. Alternately, you can use the Info panel and begin drawing the marquee when your pointer is at the X and Y coordinates of 100 and 100. The marquee can be drawn with or without the Shift key, as long as you watch the W and H values in the Info panel to make sure the marquee is 100x100 before releasing the mouse button. -
Can a selection made with the Rectangular Marquee tool be anti-aliased?
No. The tool doesn't have an anti-aliased option. -
How can you toggle between the Lasso and Polygonal Lasso tools in the middle of making a selection?
With the Lasso tool active, hold down the Alt (Option) key and release the mouse button to switch to the Polygonal Lasso. When the Polygonal tool is active, hold down the Alt (Option) key and start dragging to switch to the Lasso tool. -
Holding down the Shift key while using the Polygonal Lasso tool will have what effect?
The angle of line being drawn will be constrained to 45o increments.
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