To create multiple slices in Photoshop that are exactly the same size, draw one slice that encompasses the full width you’d like all the slices to take up, switch to the Slice Select tool, and then click the Divide Slice button in the Options Bar and choose your options in the resulting dialog. This tip comes in handy when you’re working on a navigation bar for a Web site. You could use guides and drag the slices with the Slice tool by hand, but this is much easier and more accurate. Tip courtesy of NAPP.
Category: Photoshop
Masking pesky trees in Photoshop
One of the most difficult things to mask in Photoshop is a tree. All those tiny branches and leaves make it obscenely difficult to remove the sky in the background, to say the least. Phong has a great little tutorial on masking a tree in a photo when there is a sky background. The tutorial will demonstrate how to extract a clean mask from the tree photo, using channels and levels.
Finding the exact center of your Photoshop document
In Photoshop you may find yourself trying to locate the exact center of a document by using a select all and dragging guides to line up with the handle points. This method works, but is tedious. Instead, use the View>New Guide menu item and use 50% as the horizontal and verticle locations in the New Guide dialog box.
Don’t crop your Photoshop image, Trim it
After scanning line art, and sometimes after working with illustrations, you’re left with unwanted white space around your subject matter. Accurately cropping it out can be tedious and timeconsuming, or you can use Image>Trim in Photoshop. The Trim dialog box offers a few handy settings you can customize. As long as the area you want to remove is either transparent or a solid color, Trim will instantly crop the canvas down to exactly where the illustration begins.
Position your Photoshop drop shadows visually
Did you know that there’s an easy way to get your Photoshop Drop Shadows right where you want them? Normally you would enter some coordinates into the Drop Shadow layer style dialog, then delete them or edit them again and again until you found just the right position for the shadows. It’s much easier to just drag the shadow around in the little preview window while the dialog box is open. The coordinate numbers will adjust to reflect your movements. This tip also works with Inner Shadows. While we’re at it, you can drag textures and patterns around in the Bevels style dialog, Satin style dialog and Pattern Overlay style dialog.
Making selections simple in Photoshop
If you’re trying to make a selection in Photoshop and the image is too dark in areas to see where you want to continue with your selection, try adding an adjustment layer above the entire image and use the Levels, Contrast or Saturation of the image. This should make it a lot easier on your eyes, and your nerves. Once you’re finished making your selection, you can throw away the adjustment layer.
Color shifting and replacement in Photoshop
The Color Replacement Tool is often overlooked by many designers… mostly because it’s a relatively new tool, and partly because it’s somewhat hidden where you wouldn’t expect to find it. It’s not a terribly difficult tool to master, and using it once will show you how often you *could* use it. In Adobe Photoshop CS it is bundled with the Healing Brush tool (another tool many people tend to “forget to use”). In Photoshop CS2, Adobe decided that it needed to be moved next door to the Brush Tool (see image at right). No matter where you happen to find this little bugger, you’re going to love what it can do for you. Lets say you want to change the color of the shirt in a photo to better match your layout. Many folks would spend a lot of time making a mask or clipping path, create a new layer and paint a color over top of the shirt, then adjust the layer transparency settings. Still others would just use Selective Color under the Edit>Adjustments menu and hope that it didn’t alter the image too much. These and other methods work fine, of course, but take much more effort than is necessary. 
To use the Color Replacement tool, choose a color to make the shirt. Then click on the Color Replacement tool icon in the tool bar. Then you’ll need to make some quick adjustments in the Options Bar. First, click the Brush size icon and adjust your brush settings. You’ll want to use a larger brush with a soft edge. Be careful not to make the brush too large though, you want to keep some control. 
Second, make sure you select Contiguous from the Limits pop-up menu and you set the Mode to either Color or Hue. These are the three main adjustments that need to be made. You can also adjust the Tolerance, but try working with the tool a little first. Now comes the fun part. You should now see the round outline of your brush with a little crosshair, just start painting over the area you want to color shift, being careful not to let the crosshair touch any color you DON’T want to shift (if it touches any other color, it will shift that color as well). 
Now that you see how easy it is to use and how well it works, play with the color modes, tolerance settings, etc… I think you’ll find it to be quite a useful tool not only for changing colors completely, but simply color correcting them as well.
Closing all layer groups (folders) at once in Photoshop
Did you know that you can close more than one layer group (folders) at a time in Photoshop’s Layer palette? You can with just two quick steps. Control + click the arrow on the left side of a Group layer (folder) in the Layer palette and choose Close All Other Groups. Now you’ll have to Control + click click the same arrow again and select Close This Group, because Adobe didn’t provide us with a “Close All Groups” menu item.
How BarneyScan ushered in the first “killer app”
There’s a great article about Display, er, I mean ImagePro… Doh! I meant Photoshop. Whatever name you remember it by, From Darkroom to Desktop – How Photoshop Came to Light by Derrick Story is a nifty, though five-years-old, article about the origins of Adobe Photoshop.
How to improve your Photoshop performance
A quick way to improve Adobe Photoshop’s performance is to visit Photoshop Preferences>Display & Cursors and select the Use Pixel Doubling option. Pixel Doubling tells Photoshop to double the size of the pixels used in the previews, which essentially lowers the resolution of the preview by half – thereby speeding up the display of previews.