Understanding selection tools: Part IV
- — 30 July, 2004 09:27
Knowing how to use a selection tool is only a small part of the entire image editing process. Understanding when to use a certain tool — or combination of tools — is what makes editing more an art form and less an exercise in engineering. In this final part of the series, we will look at some of the finer points and the less obvious features of selection tools.
We have, in the past, covered the idea that selected areas can be edited by using <Shift> (add new area to the selection) or <Alt> (subtract new area from the selection), thereby making a new selection. Likewise, selecting the opposite of what you want (Select-Inverse), can be an easy shortcut.
These are only a few of the techniques you can use, and many more are at the tip of your cursor. One of the most useful selection tools can be found in Photoshop Elements 2. Unsurprisingly, it is called the Selection Brush Tool (look for the icon with a paintbrush touching a small square — see picture). It’s used like a normal paint brush, but instead of painting colours, it paints a selected area. It can also be used in combination with other tools such as the Marquee or Magic Wand.
One or more frustrating aspects of image editing is not knowing the full capabilities of the program. This is frequently a result of buried items or contextual menus that only appear when another icon is clicked first. If you look under the Select or Selection menu of most programs, it would be fair to assume you’re seeing the full range of options available when you make a selection. Not so fast.
If, for example, you want to rotate your selection marquee in Photoshop Elements, you have to make a detour by heading to Image-Rotate (even though you are not rotating the image) and choosing an option from the menu. Take care with what you choose here — some features will alter the entire image, others only the selected area. Finally, if you don’t have anything selected in your picture and you go to the Image-Rotate menu just to see what may be available, there is no mention of options that can be used for selections, such as Free Rotate Selection. If they were greyed out, this would at least give you a hint that they exist, but they are simply missing. Make a selection and the items magically appear.
To rotate a selection in Photoshop, right-click on the selection and choose Transform Selection or Free Transform from the menu. Use the handles to drag or rotate the areas.
Saving a selection
It is not unusual to spend considerable time getting the selection exactly the way you want it, but what do you do if you run out of time or want to modify the selected area later? If you use Photoshop or Photoshop Elements, the answer is simple: save it. Just like any other change you make to a file, it is possible to save your selected area. There is one important caveat — you need to choose a file format that supports this technique. Forget about using JPEG or GIF. In these cases it is best to use the program’s ‘native’ format such as PSD or PDD. Start by saving the file in a supported format. To do this, click File-Save As, choose PSD or an equivalent file type, type in a file name and click the Save button.
Once you have made your selection, choose Select-Save Selection from the menu. Type in a name for your selected area and click OK. Next, save the image file (<Ctrl>+S) to ensure the changes are updated. To reload a saved selection, go back to the Select menu and choose Load Selection. If you have saved more than one, choose your option from the drop-down list. Note also that when reloading a selection, you can use additional tricks such as Add or Subtract.
Feathering and anti-aliasing are useful techniques for smoothing the boundary between a selected item and its back-ground. Unfortunately, they can also introduce unwanted pixels and incongruous colours. Programs such as Paint Shop Pro and Photoshop (but not Elements) have a defringe option that can reduce the impact of these stray pixels. You’ll find this option hidden under Layers-Matting-Adjust (Paint Shop Pro 8) and Layer-Matting-Defringe (Photoshop). To use defringing properly, you will need have a basic understanding of layers. None-theless, it is worth spending a little time experimenting with this technique — it can make many pasted areas look more natural.