For photographers, perspective is both a blessing and a bane. There's no doubt it's a powerful way to add impact. Taking a picture from an angle, or using a wide-angle lens, gives depth to a two-dimensional image, often with striking results - see FIGURE 1.
The trouble comes when you need to edit that cleverly taken image. Steep perspective looks good through the viewfinder, but it also makes it virtually impossible to correct or accurately duplicate picture elements from one part of an image to another.
For this reason, Photoshop CS 2.0's new Vanishing Point filter, which compensates for picture perspective, has become nearly indispensable to me. I don't think it's simply personal preference, either: of all Photoshop CS 2.0's vaunted features, such as smart objects and Adobe Bridge integration,
Vanishing Point should make the greatest difference to digital image editing.
Although it's a rather clunky implementation, the Vanishing Point filter is fairly easy to use. Photoshop opens a separate editing interface on to which you can draw perspective planes - most images will have more than one - on your photo.
Such planes usually point towards the "vanishing point" which, as any art student will tell you, is the imaginary point on the horizon where all parallel lines in the same perspective plane converge.
When you use one of the Vanishing Point's cut-down set of editing tools - Marquee, Paint and Clone Stamp - inside one of these planes, it automatically adjusts for perspective.
To make things easier, the perspective planes are highlighted in the Vanishing Point interface, so you always know when you're working inside a plane.
Even better, although not visible outside the Vanishing Point window, the perspective planes are stored in JPEG and TIF images - so you have them on hand and can reuse them at a later date.
If there's any justice in the graphics world, Vanishing Point should change the way Photoshop users edit images. It's not, as I first thought, just a method to help build accurate perspective when creating image collages.
Instead, it really shines when it comes to cleaning up images. The Clone Stamp tool, which removes artefacts by applying a sample of one part of an image over another, is virtually redundant in any image with perspective, but thanks to Vanishing Point, it has a new lease on life. And if you've ever spent painstaking hours attempting to clone image elements where the subjects are in perspective, you'll join me in celebration.
Taking a fence
Let me show you how Photoshop CS 2.0's Vanishing Point feature works with a real-world problem. The original image of a fence (FIGURE 1) features broken boards and rails, a cluttered bedding area and an ugly strip of patchy grass. Thanks to the steep perspective, correcting all three would normally be tricky. But not with the Vanishing Point filter.
I created two perspective planes. The first (see FIGURE 2) was drawn along the fence, matching the nodes of the plane to the top and bottom of each end of the fence. A perpendicular plane was then stretched out from this to extend along the ground.
Once these planes were drawn, correction was simple. The Marquee tool was used to select an existing fence board and clone it over the gap. The size of the board was automatically adjusted as it was pasted. The same process was used to paste over the damaged horizontal rails in the foreground.
The Clone Stamp tool was employed on the perpendicular plane to duplicate patches of grass. You can't expect miracles: when I cloned the grass from a distant source, there was some inevitable blurring as it was scaled up in the foreground. But otherwise the effect is both quick to perform and pleasing to the eye - see FIGURE 3.