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Computer Editing: Special Effect Video Filters

Computer Editing: Special Effect Video Filters

Take advantage of your video editor's special effects filters, just don't overdo it.

Last month, we took a look at corrective filters; those small programs that let you fix unexpected problems in your footage. This month, we'll examine special effects filters.

Even more than corrective filters, special effects filters come in an almost mind-boggling assortment. In a typical video editor's filters menu, you'll find such choices as Blur, Border, Distort, Perspective and dozens more.

All special effects filters let you alter some aspect of your original shot in order to benefit your video. Some of these filters mimic techniques that traditional photographers and videographers were able to use long before the modern electronic era.

Blur Filters
The blur filter, which is built into nearly every editing package isn't far removed from the old-fashioned photography trick of putting a clear glass plate in front of the camera's lens, then smearing it with petroleum jelly for a blurred halo effect around a portrait shot.

But where the traditionalist had a small number of blur effects to choose from, today's video editor has dozens. Not only can you apply a blur filter to your scene, you can choose between simple blurs, motion blurs, gaussian blurs, ripples, wind and dozens of other interesting blurs.

Within most of those choices, you have control over parameters such as direction, amount, opacity and duration of the blur. You can blur inside a matte, blur after applying a color filter or blur along the border of two separate video layers in order to make them look more like a single, seamless composite.

As with corrective filters, special effects filter possibilities are so vast that we'll just study a couple of common examples to show how you might use them to enhance your footage.

Let's start by looking at how you can combine a simple blur filter with your software's matte capabilities to focus the viewer's attention on an individual figure in a scene.

Blur With a Purpose
For our example, we'll take a typical shot of a class of elementary school kids and use a blur filter to single out one face for use in a title sequence.

Figure 1a shows our young star standing in the second of three rows of kids. In Figure 1b, we've duplicated the footage onto a second track and used an oval mask to isolate the one face we want to highlight. In Figure 1c, we apply a gaussian blur to the foreground image, obscuring the rest of the class. If a single layer of blur doesn't achieve the look you desire, it's perfectly OK to stack another until you get what you want.

In order to make the effect less harsh, we'll add yet another filter feather-edge to the blur layer, making the transition from the sharp foreground to the blurred background gradual.

Add a title layer and voil, the other kids fade into the background while our blurred-free hero indicates that he's indeed the star.

Filter Combinations
Next, let's combine a pair of filters to create a sequence that makes our modern-day video look like something from the Silent Film era.

You can often distinguish historical photographs by the fact that they were made before the advent of full-color film processing. So, the first step in our quest to make our modern video appear aged is to change the color balance of our existing footage.

In the Image Control filters settings, first check to see if your software has a pre-configured sepia setting. Sepia prints are a type of old-fashioned photographs composed of varying shades of a brownish-yellow hue, rather than full-color or black and white. Most people take one look at sepia-toned images and assume they are old. This filter's simple application will start to give your footage an old-time feel.

If your editor doesn't have this filter, don't worry. First, use a hue and saturation filter (reducing the saturation to zero) to remove all of the color information from the clip. This makes the video black and white (if you have a black-and-white filter, you can try that instead). Next, add a color filter on top of the saturation filter in the effects chain. The result will be a monochrome (one color) image. You can try to simulate a sepia image with the right colors, but test some deep greens and blues for some interesting effects as well.

The Aged Effect
The next attribute of many Silent era films is the fact that in those days movie projectors imparted a flickering quality to their screenings.

Dive into your filters menu again and search out the strobe control (called Posterize Time in Premiere). But be careful, a little of this effect goes a long way. Too coarse a setting and you'll drive your audience nuts. Your goal is a subtle flicker quality, not a full-blown strobe effect.

For the videographer looking for the ultimate silent film effect, add-on filter packages available from commercial vendors can provide you with such realistic touches as moving film scratches, "lint in the gate" effects and even cool transitions that make it appear that your film has broken.

But for most uses, adding sepia tone and a subtle flicker filter are enough. Dress the kids in old-time clothing or Keystone Cops attire and you'll virtually guarantee yourself a fun-filled day making your own silent film classics.

The Final Word
Again, the examples we've stepped through here are just the tip of the iceberg. The real lesson is that filters are some of the most powerful tools built into your editing software.

In the end, the best way to learn the capabilities of your particular video editing software package is to follow the advice offered in that old vaudeville joke where the New York taxi driver is asked, "What's the best way to get to Carnegie Hall?" and the cabby fires back the single word answer: "Practice."

[Sidebar: A Matter of Taste]
Back when computerized desktop publishing first gave budding page designers access to a zillion typefaces, it became common to see documents that looked more like ransom notes than artistically designed, professional-looking communications.

That same trap awaits the novice videographer diving into the world of special effect filters for the first time.

During the learning phase, it's perfectly OK to try anything and everything. Have fun and go nuts. But with all the tricky effects that modern editing filters put in your hands, there's a temptation to use filters simply because it looks cool.

The pros understand that the only way to make a special effect truly special is to use it sparingly and with good design principals in mind. After all, just because you're software has some cool filter called a Bubble Effect doesn't mean you have to go looking for a place to use it in your very next video.

Be patient. Someday you'll have a shot of one of your kids surfacing from the pool, a pot boiling on the stove, or a champagne toast, and that weird special effect filter will suddenly make perfect sense.

[Sidebar: Filter Control Terminology]
Not all programmers use the same terms to mean the same thing. Even the simplest effects such as blending two scenes together at an edit point might be called "dissolve" in one package, "cross-dissolve" in another and "cross-fade" in a third.

Similarly, don't be surprised if you go to apply a wind-blur effect that one package uses the term "direction" and another uses "angle" to indicate the exact same parameter.

Again, experience is the best teacher, so as you explore your software and com across filter terms or parameters that you aren't familiar with, try them out.

[Sidebar: Filter Cut and Paste]
Since editing filters are really just text-based lines of code, many programs let you copy and paste your filters. After you have applied an effect and tweaked it to perfection, some programs will let you simply copy those settings and paste them onto other shots. Check your manual to see if you can do this with the program you use.

Tags:  November 2002
Bill
Davis
Fri, 11/01/2002 - 12:00am