Working with Selections

Working with Selections

Q1:	What is anti-alias?
A1:	Anti-aliasing softens what would otherwise be a jagged edge. For example, when you make a Lasso tool (L) selection, it follows the square pixels to create a "stepped" selection. Clicking on the Anti-alias checkbox in the Option Bar will smooth that selection to make the edges look less jagged. The edges look blurry zoomed in, but at actual size (zoomed in at 100%) the edges look smooth.
Q2:	How do I move a selection?
A2:	To move the selection edges (rather than the pixels), use a selection tool (instead of the Move tool) and click-and-drag within the selection.
Q3:	How do I save a selection?
A3:	With your selection active, go to the Select menu and choose Save Selection. This will save your selection as an Alpha channel that can then be reused later through the Load Selection command (under the Select menu). (See "What is an Alpha channel?" in the Selecting section of this chapter.)
Q4:	How do I make a selection based on text? I'd like to make a selection around text I've created. What's the best way to do this?
A4:	There are a couple of options: Use the Type Mask tool to create the selection as you type. Create your type with the Type tool (T), which automatically creates a Type layer in the Layers palette. Then Command-click (PC: Control-click) on the Type layer's thumbnail to load it as a selection. (This method offers the advantage of having an editable Type layer to use later if required.)
Q5:	I used to Command-click (PC: Control-click) on a layer name to select its contents but it doesn't seem to work in CS2.
A5:	There's been a slight change, because now when you click on the layer name, you're selecting just the layer, not its contents. Now you must click on the layer thumbnail with the Command (PC: Control) key held down to select the contents of the layer.
Q6:	How can I smooth the edge of a selection? I already made a selection but the edge looks a little too jagged. Is there a way to smooth the edges? (I tried feathering and that didn't help.)
A6:	There is a command under the Select>Modify command called Smooth, and sometimes that can help. Or, with your selection in place, press Q to change to Quick Mask mode and try using Filter>Noise>Median.
Q7:	Is it possible to hide the selection edges (a.k.a. marching ants )?
A7:	Yes, just press Command-H (PC: Control-H).
Q8:	Why do I get a message that says "the selected area is empty"? I am trying to select and move part of a layer, but I get a warning that "the selected area is empty." I'm sure I selected some pixels. Why am I getting this message?
A8:	This message appears when you are trying to move a selected area but that part of the layer is transparent. That usually happens when it looks as though you have selected part of a layer, but you actually have a different ("wrong") layer as your active layer. Make sure you click on the name of the layer you want to work on, then you should be able to move the pixels.
Q9:	How do I make a selection the same size as part of another image? I want to select an area on one image that will "fit" in an area on a second image. I'm having a hard time getting the size just right. Any suggestions?
A9:	Make a selection on your second image that is the size you eventually will take from the first image. Using a Marquee tool (or some selection tool but not the Move tool), click-and-drag the selection from the second image into the first image. Go back to the second image and deselect (Command-D [PC: Control-D]). Return to the first image and position the section in the correct location, then switch to the Move tool (V). Drag-and-drop from the first image to the second image.
Q10:	How do I make a series of selections of the same size?
A10:	Just change the Style for the Marquee tool to Fixed Size in the Options Bar and type the size you want in the Width and Height fields. Then click once where you want a new selection of that size. The position of your cursor will create the top-left corner of the Marquee selection, in the size you indicated in the Options Bar. Press-and-hold the Shift key as you click to make multiple selections in the same document, or leave the setting in the Options Bar so you can make several selections at this fixed size in other documents (as you have changed the default setting for the tool).
Q11:	How can I make it easier to see what I'm doing when using selection tools? I'm trying to use my Lasso to select the edges of an object, but there's very little contrast so it's really hard to see the edges. Is there any way to help with this?
A11:	Try adding an adjustment layer from the Create New Adjustment Layer pop-up menu, such as Hue/Saturation, and really over-adjusting the Hue (or add a Levels adjustment layer and over-adjust the Levels). This can make it easier to see the edges. Once you've made the selection, delete the adjustment layer by dragging it to the Trash icon at the bottom of the Layers palette.
Q12:	How do I select one color ?
A12:	If the color is all in one area, try the Magic Wand (W). If the color is in various parts of an image, try using Color Range from the Select menu. This lets you "eyedrop" a color and/or use the Fuzziness slider (and additional droppers) to fine-tune what you are selecting.
Q13:	How do I select and change all areas of the same color? Is there a way to select all areas of the same color and change them all simultaneously to another color without selecting each area manually?
A13:	Try Image>Adjustments>Replace Color. This feature lets you "eyedrop" a color to select it, and then replace it with some other color by changing the Hue and Saturation (this works relatively well). Or select one area of color using any selection tool you like, and from the Select menu choose Similar. Now you can choose a new color by clicking on the Foreground color swatch, picking a color in the Picker, and pressing Option-Delete (PC: Alt-Backspace) to fill your selection with your new color.
Q14:	Is there a quick way to select an object on a white background?
A14:	Here's a very quick method: press Command-A (PC: Control-A) to Select All. Then hold down Option (PC: Alt) and click with the Magic Wand (W) on the white area. This will remove the white from the selection and you'll be left with your object selected. An alternate method would be to click in the white area with the Magic Wand, then choose Select>Inverse. The advantage of the first method is that the concept works for various situationsfor example, a hot air balloon on a clear, blue sky. Make a Marquee selection around the balloon and part of the sky. Then press Option (PC: Alt) and click with the Magic Wand on the blue sky to remove the sky, selecting only the balloon.
Q15:	How do I select right to the edges of the document window? I am trying to select part of an image that goes right to the edge of the document. It is difficult to drag the Lasso right along the edge of the image. How can I make sure I don't miss anything?
A15:	As long as you start using the Lasso tool (L) inside the document window, you can drag it outside the document window itself (meaning you're dragging onto your desktop or outside the physical document) and then return inside the window. The selection will stop right at the edge, and there's no worry about missing any pixels.
Q16:	Why can't I select something?
A16:	Make sure: You have chosen the correct layer as your active (target) layer in the Layers palette. You are not on a Type layer.
Q17:	How do I select the darkest (or lightest) parts of an image?
A17:	From the Select menu, choose Color Range. Rather than clicking with the Eyedropper,from the Select pop-up menu, choose Shadows (or Highlights).
Q18:	What is the warning "no pixels are more than 50% selected" telling me?
A18:	This suggests that you have made a selection that will not show the selection edges. This is due to the combination of the Feather amount and the size of your selection. It typically happens when you make a small selection with a high Feather amount. You will still have a selection, but you will not see the "marching ants." Also, if you were to run a filter, paint, etc., the effects would be minimal, since you have " barely " selected any pixels.