Selection:
| marquee |
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The marquee tool
If you click and hold, you'll see that it's really four tools in one: You can select a rectangle (if you hold down the Shift key, it'll give you a perfect square); go for an oval (the Shift key will make it a circle); select a single row of pixels, or a single column.
But usually you'll want a more complex selection than is provided by these simple shapes. Here's the first really important trick: You can add and subtract from selected areas. To add to a selection, hold down the Shift key and make another selection; your first selection will be added to your second one.
To subtract, use the Alt key to make a selection and your second selection will be subtracted from your first. By mixing and matching, adding and subtracting, you can get some very complex shapes.
Lasso
| lasso |
 |
The tool next to the marquee is the lasso. It allows you to draw selection paths freehand with a mouse. If you click and hold, you can change the tool so that you can draw polygons. Again, you can add and subtract to these selections by using the Shift key and the Alt key. This is a great tool for detail work. You can zoom way in with the magnifying glass tool (hit the space bar with the Control key to zoom in, or the space bar and the Alt key to zoom out) to add or delete pixels.
Magic Wand
| Magic Wand |
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The next selection tool, the magic wand, will select all the same-color or similarly colored adjacent pixels. Double-click on the magic wand tool and you can change its color sensitivity. So if you set the tolerance to 0, you will only select adjacent pixels that are exactly the same color; the higher the number you type into the tolerance field, the less similar the adjacent pixels need to be in order to be selected. You can also use the Shift and the Alt keys to add and subtract to these selections.
Select menu
Select All, Deselect, Inverse, Select None, Save Selection.
do some samples on local drive>>>