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Adobe Photoshop CS2

Mar 1, 2006 12:00 PM, By Glenn Campbell, Area 51

The Key to Realistic Composites

Area 51 is an independent visual effects firm with seven to 10 employees who all wear multiple hats. For example, my title is visual effects supervisor, but I'm also a hands-on animator, lighting, and composite artist. Because much of our work is for episodic television, the pace is extremely hectic and client budgets are tight. At the same time, with the emergence of HDTV, our work must always have feature-film quality and resolution.

We're able to consistently meet this challenge because the members of our team come from traditional filmmaking backgrounds, bringing lots of tricks from the film world to the digital world. When I meet “keyboard kids,” I always tell them that software can enhance their artistic ability, but not confer it. Adobe Photoshop CS2 software is the godsend I rely on every day to make the most of what few artistic skills I have.

To create composites, I routinely follow a six-point checklist: color balance, brightness and contrast, key light direction, perspective, amount of blur, and amount of grain. Addressing these visual attributes for each and every layer will make a composite appear far more realistic and meet film-quality standards. I use Photoshop CS2 constantly to facilitate the process. Photoshop tools make it easy.

In early 2005, Area 51 created visual effects for the cable TV miniseries Into the West, a Steven Spielberg and DreamWorks Television production that aired last summer on TNT as a cycle of six weekly two-hour films. The story spans 65 years of U.S. history, from 1825 to 1890, and depicts major events such as the Gold Rush, the building of the transcontinental railroad, and the Native American massacre at Wounded Knee. The emphasis was on the characters — there were 250 speaking roles — and the majestic scenery. Ideally, viewers would be surprised to learn that there were any visual effects at all.

One of our assignments was to enhance the establishing shots of a frontier town, which was filmed on location at a specially built set in New Mexico. The live-action footage showed a basic assortment of period structures and about 150ft. of railroad track against a backdrop of low hills. To make the scene look convincingly like a 1870s winter in the Dakota Territory, we needed to add extra buildings, smokestacks, fires, smoke, snow, and a train. We also needed to replace the hills with a snow-covered mountain range and make the sky cloudy.

Color Balance

To add more buildings and other elements to the live-action clip — our background plate — we gathered images from stock and archival collections. These images varied widely in photographic vintage, quality, and appearance. To make our composite look realistic, we needed to match the color of the buildings with those in the original footage. Photoshop CS2 gives you several ways to perform this task.

The Match Color command reads the color scheme of one image or layer and instantly matches it to another. This feature gets you in the ballpark immediately; afterwards, you can add or subtract colors using Color Balance adjustment layers to fine-tune the look.

Brightness and Contrast

To appear realistic, all elements in a composite image must appear to be shot at the same time of day, in the same season of the year. Nothing can be whiter than the whitest white of the background plate, and nothing can be blacker than the blackest black. Ninety percent of the time, those two extremes define the range of brightness and contrast within which you have to work.

To lighten or darken images accordingly, there are multiple choices in Photoshop CS2. You can use the Brightness and Contrast tool to automatically start the process, and then use Gamma adjustment layers to set values or the Levels dialog box to adjust curves. Shadow/Highlight correction lets you quickly adjust the contrast of over- or underexposed areas while preserving correctly exposed ones. Regardless of what approach you take, though, you're going to need your artistic skills to eyeball the images until you're satisfied.

Key Light Direction

All elements in a good composite also must appear to be lit from the same direction. This step is easy to overlook, yet it is critically important. In our live-action clip, the sunlight was coming from the upper left side of the frame, from behind the camera. As we added buildings, mountains, and other elements, we used basic Photoshop tools to clone and flop them as necessary to make sure the light was hitting them from the same direction as the background footage.

Perspective

The two best Photoshop tools for digital matte paintings and composites are both new with CS2 and they address the issue of perspective: Optical Lens Correction and Vanishing Point.

Optical Lens Correction automatically fixes a wide range of common camera lens discrepancies. You can eliminate barrel or pincushion distortion, chromatic aberration, vignetting, and perspective flaws in all three dimensions in just one pass. For Into the West, we used this tool to alter the perspective of the buildings to seamlessly match those in the background plate.

Vanishing Point lets you easily lay out the visual perspective of a background plate as a matte painting. You define your perspective planes visually with the grid tool, and then paint, clone, and drag objects around corners and into the distance, eliminating hours of retouching. To extend a cliff face, for example, we used Vanishing Point to clone and move rocks and landscape elements while keeping them in perspective.

Blur

In a realistic composite, the amount of blur of an added element needs to make sense in the context of what's around it. While there's no automatic way to match the look you need, the blur filters in Photoshop CS2 let you easily add Gaussian, lens, motion, or radial blur effects. Conversely, the new Smart Sharpen filter counteracts common blurring by automatically enhancing edge details, and it includes advanced options for adjusting shadows and highlights. I was initially wary of the artificial sharpener, but have found that it works surprisingly well.

Grain

Like blur, the grain of every element in a quality composite must match the background plate. The Film Grain filter in Photoshop CS2 adds an even amount of noise to the shadows and mid-tones of an image while applying a more obvious pattern to the highlights. The Texture Grain filter gives you lots of choices for adding grain styles such as regular, soft, sprinkles, clumped, contrasty, enlarged, stippled, horizontal, vertical, and speckle.

The Spot Healing Brush, another new tool in Photoshop CS2, is ideal for visual effects artists, and it came in handy for Into the West. By automatically analyzing and selecting the best pixels to use, the Spot Healing Brush enables you to easily click or paint away flaws, remove entire objects, and heal across layers in blending or sample modes. We used it on the cloud and mountain layers to clean up scratches, dirt, and other blemishes in our images. While not a complete substitute for the trusty Clone Stamp tool, it's a powerful companion.

You can either use many of the tools in Photoshop CS2 as shortcuts or work out your own techniques as I've done over the years, or both. The program gives you dozens of ways to get where you need to go visually, and none of them are wrong. Such versatility forms the heart of Photoshop. The ability to quickly isolate elements within an image, extract mattes, manipulate attributes, and render in more than two dozen file formats (including HDRI and 32-bit alpha channels), as well as the program's complete compatibility with Adobe After Effects software, are why PhotoshopCS2 is essential for visual effects artists — and for creating composites with invisible layers and total realism.

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Founded in 1992 by Tim McHugh and based in Burbank, Calif., Area 51 creates visual effects for film and television. The firm earned Emmy awards for the miniseries Frank Herbert's Dune and Children of Dune, an Emmy nomination for the series Space: Above & Beyond, and a Monitor Award for the series Dark Skies. Glenn Campbell earned a Monitor Award for his work on the series Viper. For more information about Area 51, call (818) 238-9660 or visit www.area51fx.com. For information about Adobe Photoshop CS2, visit www.adobe.com.

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