Teach Yourself Adobe Photoshop CS2.pdf - Online Public Access ...

This document was created by an unregistered ChmMagic, please go to http://www.bisenter.com to register it. ThanksMotion BlurWhen we see lines drawn behind a car, a cat, or a comic strip character, we instinctively know that the subject is supposed to be in motion.Those lines represent motion blur, which is actually a photographic mistake caused by using a slow shutter speed on a fast subject. Theimage's subject appears totally or partially blurred against the background because the subject actually traveled some distance during thefraction of a second that the camera shutter was open.In the early days of photography, motion blur was a common occurrence, primarily because shutter speeds were slow, and film sensitivitywas not very great. Today, motion blur is unusual, unless the photographer is capturing the subject this way on purpose by using the leastsensitive film available or by using a small lens opening and a correspondingly slower shutter. If you want to try to approximate the effect ofmotion blur, Photoshop gives you a tool that can do it.The Motion Blur (Filter Blur Motion Blur) filter can add the appearance of motion to a stationary object by placing a directionalblur for a predetermined distance. In the Motion Blur dialog box, shown in Figure 14.14, you can set both the distance and direction of theblur according to how fast and in what direction you want the object to appear to be traveling. The distance sets how much of a blur isappliedor how far the original image is "moved." The angle sets the direction of the blur. To adjust, drag the Radius slider or enter precisevalues into the field next to it. The trick, however, is to select the right area to which to apply Motion Blur. To get a convincing blur, youneed to blur the space where the object theoretically was, as well as to where it theoretically has moved.Figure 14.14. Using the Motion Blur filter is tricky at best.