Notes *9
The Magnetic Lasso Tool will snap to areas of differing contrast, the greater the contrast difference the better it works.
You can set the brush width from 1 to 40 pixels. The larger it is the further away from the edge the cursor can be and still snap in place. It will also wander off more easily if it finds a better contrast ratio with in the brush width. As you are making the selection you can change the brush size by using the Left [ and right ] square brackets to better suit the needs of a particular area of the image.
After selecting the Magnetic Lasso, you can change the cursor from the Icon to a Circle with a + sign in the center, by pressing the Caps Lock key. The circle is the actual pixel size of the brush. This is a more visual representation of the tool.
Begin by clicking the mouse to set the first anchor point. Move the cursor around the image to be selected (don’t hold the mouse button down). If the marquee starts to wander off, you can set additional anchor points by clicking the mouse button. If things don’t go exactly right, you can back up, one or several anchor points, by pressing the delete key.
You can switch between the Magnetic Lasso and the Lasso Tool by holding down the Option Key as you are dragging . To switch between the Magnetic Lasso and the Polygonal Lasso Tool, hold down the Option Key and click the Mouse button. Continue to hold down the Option key as you click to keep the Polygonal Lasso Tool active. When you do a normal click it will revert to the Magnetic Lasso Tool.
This is handy if there is insufficient contrast for the Magnetic Lasso Tool to work properly in a portion of the image., or if you have a long straight section to select.
It is generally easier to Zoom in on a portion of the image while selecting. By holding down the Spacebar while selecting the Hand Tool will be displayed and you can pan around the image as needed.
If you can not make a clean selection in a portion of the image, let it go. Later you can nudge things into place with the Selection Brush.
Notes *10
The Magic Wand Tool makes selections by finding and drawing marquee’s around areas of the same or similar color. Check the Contiguous box if you want to constrain the selection, such as to a single red rose. Un-check Contiguous if you want to select all of the reds in the image. A low Tolerance will keep the color selection small or narrow. A high Tolerance will select a wider range of colors and brightness. Make the first selection by clicking on the image. Add to the selection by holding down the Shift key and clicking in another area of the image. Likewise you can subtract from the selection by holding down the Option key. After the majority of the image is selected, it is often easier to do some clean up with the Selection Brush, then to try to select every last pixel with the Magic Wand Tool.
Don’t over look the fact that it might be easier to select the background then the object itself. You can then Inverse the selection to have the object selected. Always look for ways to make the process easier.
Notes *11
The Selection Brush functions just like a paint brush, except it paints a selection instead of colors. As you are making the selection you can change the brush size by using the left [ and right ] square brackets to better suit the needs of a particular area of the image. You might want to start out with a large brush for selecting the majority of the image, then switch to a smaller brush to nudge the selection in to tight places. Add to the selection by holding down the Shift key. Subtract from the selection by holding down the Option key. Clicking the Mask box will add a Rubylith color to the selected area rather than putting a Marquee around it.
You can use the Selection Brush to clean up selections made with other selection tools.