- Mar 10, 2006
Rotating a Layer vs. the Entire Document
Photoshop has two sets of rotation commands. One rotates layers and objects, and the other rotates everything ( Figure 3.27 ). When you want to rotate just one layer or object (like a path), select a layer in the Layers palette, then choose a command from the Edit > Transform submenu.
Figure 3.27 The original (left) has two layers: One with the triangle, and the other with the letter N. In the center image, only the triangle layer is rotated, using Edit > Transform > Rotate 90° CW. In the right image, the entire document is rotated, using Image > Rotate Canvas 90°CW.
When you want to rotate absolutely everything in a Photoshop document, including the document dimensions, choose a command from the Image > Rotate Canvas submenu.
Rotating an Image the Fast, Precise Way
When you want to straighten an image but you don't know the exact angle you need, the Measure tool can help you ( Figure 3.28 ):
- Select the Measure tool. It normally hides in the toolbox under the Eyedropper tool; if the Measure tool is hidden, hold down the mouse on the Eyedropper tool to reveal it.
- Drag the Measure tool along a line in the image that should be perfectly horizontal or vertical.
- Choose Image > Rotate Canvas > Arbitrary. The angle from the Measure tool is entered automatically, so just click OK and the image should straighten perfectly.
Figure 3.28 Dragging the Measure tool along a line in the image that should be vertical (top with detail view); Rotate Canvas dialog box with the Measure tool angle entered automatically (center); canvas straightened by the angle entered in the Rotate Canvas dialog box (right).
Rotating in Camera Raw or Bridge
Adobe Bridge is great for applying 90-degree rotations to a bunch of images at once. You'd usually do this when you import scans or digital camera photos that don't automatically rotate. Camera Raw is the best place to straighten many crooked digital camera photos at once. Use Photoshop for any remaining rotational needs that aren't met by Bridge or Camera Raw.
To apply 90-degree rotations in Bridge, select an image and click one of the Rotate icons at the top of a Bridge window ( Figure 3.29 ). Note that you can select multiple images and rotate them all at once much faster than you can in Photoshop.
Figure 3.29 In any Bridge window, you can rotate one or more selected images 90 degrees at a time using the two rotate icons in the middle of the toolbar.
Camera Raw also sports these same Rotate icons. However, Camera Raw also lets you rotate at any angle with its Crop tool. If you drag a crop rectangle in Camera Raw and position the pointer outside the crop rectangle, you can drag to rotate the crop rectangle ( Figure 3.30 ). The rotation takes effect when you open the raw image in Photoshop; rotation and cropping are applied during the conversion.
Figure 3.30 Dragging from just outside the top right corner of a Crop Tool rectangle to rotate an image in Camera Raw.
In both Camera Raw and Bridge, the rotation information is saved with the object's metadata, which means you always retain the complete original image in case you want to edit the rotation later.
Instant, Direct Straightening
Both Adobe Camera Raw and the Lens Correction filter include a Straighten tool that directly corrects crooked images. If you thought the Measure tool trick was cool (see "Rotating an Image the Fast, Precise Way", earlier in this section), the Straighten tool does the same thing in fewer steps:
- Open a raw image in Camera Raw, or if you already have an image open in Photoshop, choose Filter > Distort > Lens Correction.
- Select the Straighten tool from the Camera Raw or Lens Correction toolbox.
- Drag the Straighten tool along a line in the image that should be perfectly horizontal or vertical (
). In Camera Raw, the crop rectangle rotates, but the image itself remains unrotated during conversion from raw format. In Lens Correction, the image immediately rotates according to the angle formed by the line.
Figure 3.31 After dragging the Straighten tool in the Camera Raw dialog box (left), the crop rectangle rotates to match, so that the image will be straightened when converted from raw format.
- Click OK when you're done making all corrections in Camera Raw or Lens Correction. The rotation is applied to the image.
Transforming with Total Freedom
In a word: Yes. The Free Transform command does it all. When you choose Edit > Free Transform, a bounding box appears around the current layer. You can, of course, use the bounding box to transform the layer. What most folks don't notice, however, is that when the Free Transform bounding box is active, numeric entry options appear in the Options bar, too! So you can move, rotate, or scale the layer by entering precise values and then pressing Return or Enter.
But for those who want to work visually rather than numerically, here's a quick guide to the Free Transform bounding box:
- To rotate, position the cursor outside the bounding box until you see the double-arrow rotation icon, and drag (
Figure 3.32 Rotating with the Free Transform bounding box (notice the Options bar).
- To scale, drag any handle.
- To skew, Command/Ctrl-drag a handle.
- When using the bounding box, add the Shift key to transform proportionally, or add Option/Alt to transform from the center.
Correcting Lens Distortion
Photoshop CS2 includes the new Lens Correction filter, which is great for removing various types of visual distortion which are usually most obvious in images shot using wide-angle lenses. Start by choosing Filter > Distort > Lens Correction ( Figure 3.33 ).
Figure 3.33 Formerly distorted vertical bars are straightened after adjusting the Remove Distortion, Vertical Perspective, and Angle options in the Lens Correction dialog box.
It's a good idea to straighten the image first. Select the Straighten tool and drag it along a line in the image that should be perfectly horizontal or vertical, and Photoshop rotates the image accordingly. If the result is just a little bit off, click in the Angle value and press the up and down arrow keys. That's usually an easier and more precise way to adjust the value, rather than dragging the Angle control.
Then, to correct the barrel distortion, increase or decrease the Remove Distortion amount. Check your progress by keeping your eye on the grid.
To correct perspective distortion, increase or decrease the Vertical Perspective or Horizontal Perspective values. It's usually easier to see what you're doing here after you've straightened the image and removed barrel distortion.
As you make corrections, Photoshop automatically sizes the image. If you think too much of the edges are cut off, reduce the Scale value at the bottom of the dialog box. Click OK when you're done.