By Christopher Grey
Published by Amherst MediaWant to photograph your subject in front of the Taj Mahal on a zero-dollar travel budget? You can drop in any background you like when you shoot photo and video subjects in front of a greenscreen. Learn how to set it up, light it, and drop it out with this excerpt from Amherst Media book Christopher Grey's Lighting Techniques for Beauty and Glamour Photography.
This excerpt from Christopher Grey's Lighting Techniques for Beauty and Glamour Photography is provided courtesy of Amherst Media. To purchase the book and learn more about the publisher, visit the Amherst Media Web site.
This is a chapter that I’ve looked forward to writing for a long time.
Removing a background, or “dropping out” a background until it’s transparent, and inserting a new scene behind the subject is often difficult. Photoshop has its Extract tool, but it’s far from perfect. There are also third-party plug-ins that will do the job. I’ve tried many of them. My favorite method—though not perfect—is greenscreen.
Greenscreen technology, along with its sister, bluescreen, relies on a very simple principle: their bold coloration is not found in skin tones and, for that reason, software can be used to easily target and eliminate the color, leaving you with a selection of the important parts of your image, which can then be magically placed against another, separately photographed and idyllic new background. The technique has been used in video for years (known as Chroma Key), and you see it in action every night on the news when the weatherperson stands in front of a map and tells you (with a great deal of error in my part of the country) the forecast for the next few days. The “map” that’s being discussed does not actually exist behind the newscaster—it’s a separate graphic that’s digitally inserted into the green or blue field behind that bearer of good or bad news.
When I began my greenscreen experiments, I used a muslin background that was dyed to the target color. It was such an ugly color that I wanted to easily pack up my “greenscreen” when it was not in use. I’ve since found so many uses for greenscreen that I decided to make a commitment: I painted my primary shooting wall green. It’s hideous, but it makes so much money for the studio that I gladly put up with it. I’ll explain more about how that works for me later.
Rosco also makes bluescreen and greenscreen paint. Unfortunately, it’s quite expensive (about $100.00 per gallon) and provides poor coverage. After trying it, I went a hardware store, chose a swatch of paint that was as close as possible to the Rosco paint, and had them mix a gallon. The “makeshift” paint cost 70 percent less and worked just as well. Image 14.1 gives you an idea of what the color looks like; however, bear in mind that the printed page may not match the real color perfectly. Note too that several shades of blue or green will do the job—just choose one that is so ugly that you won’t see it in flesh tones or in most clothing.
There are plenty of software programs and plug-ins that you can use to drop out a greenscreen. If you’re a software developer or someone who has a better solution than what I’m about to propose, please let me know ([email protected]). I promise I’ll try it and let my little corner of the world know how I feel about it.
My favorite green/blue screen application is Ultimatte’s AdvantEdge, a Photoshop plug-in that, for what it does, is quite fairly priced. Ultimatte’s plug-in also works with Final Cut Pro video editing software, although the license fees may be different. You can try the fully functional software for free on their web site (www.ultimatte.com), but you will not be able to save a non-watermarked image without the special dongle key that you get when you actually purchase the goods. AdvantEdge works with both green and blue.
When I set my lighting for greenscreen, I typically use two strip lights, one on each side of the background and feathered so the exposure value is no more than 2/10 stop off over the entire background. Although it’s not entirely necessary to do so, I use a dedicated power pack for these two lights. I’ll also put a black bookend or other gobo between the lights and the camera, to prevent any spill or flare.
Now, your experience may dictate otherwise, but mine says that light on the greenscreen (or bluescreen) background works best when it’s metered to read around a stop under the main light. The extra saturation seems to help the software make a clean extraction of the subject. I also think it best (unless the situation warrants it) to keep the subject at least 8 feet from the background wall (farther is better) and to flag off as much bounce light as possible. The software will read any colored spill from the background and eliminate it wherever it falls on the client. In other words, if 25 percent of the light bouncing from the background onto the subject is green (or blue), then 25 percent of the subject will be made transparent, allowing 25 percent of the background to show. This is a tool that can be used to your advantage, but you must understand how it can impact your images before diving in.
Ready? Begin by setting and metering the two background lights so they’re as even as possible across the width of the background you wish to use. For single subjects, this is quite easy, especially if you’re shooting with a telephoto lens and can narrow the perspective between what’s lit evenly and what is not.
With your subject placed at least 8 feet in front of the background, set the main light in place and power it to 1–11/3 stops over the background light as a starting point. Remember that the main light will have some influence on the background (another reason to keep the subject as far from the background as possible). When the influence of the main light is figured into the equation, the ratio of main light to background light will be close enough for government work. Note that it’s a ratio that’s not carved in stone. Close counts—however, it just seems easier for the software to remove the background if the ugly color is a bit darker. Could you find a color that’s a bit darker and light everything evenly? Possibly, but given the degree of difficulty involved with lighting a background large enough to accommodate a group (perhaps one that stretches across the expanse of the backdrop), you should not allow the background to be too dark or you’ll have to make some adjustments by hand, a tedious process. You can’t allow the background to be lit by just the main light, either, as shadows may come into play that might be difficult to remove.
So, here’s the first image (14.2). Notice that the model’s hair is separated in a number of places, sometimes only a few strands wide, allowing green to show through. Also, notice her tattoo. The green in the frog will also become transparent, at least to some degree. I’ll show you how to deal with that in just a bit. (Note: This chapter isn’t meant as a software tutorial beyond the very basics. I won’t be providing step-by-step instructions on how to use the software—just great information on what you might do with it.)
Before using AdvantEdge, you’ll need to duplicate the original image layer.
You’ll need to sample the background color. Once that is done, the program will let you soften the blend of color densities in the background and clean up minor imperfections such as where a wall would meet the floor. You’ll also be able to adjust for color spill, eliminating most green fringing.
When AdvantEdge has completed its cycle, you’ll see that the second layer has been rendered transparent. Deselect the first layer to judge the quality of the image. I find that duplicating the transparent layer will often add density to a model’s hair and clothing. Although you will not see this as a transparent background (because the paper is white), you can see how effectively the green was removed. See image 14.3.
As I mentioned above, the green in the frog tattoo was rendered transparent. Photoshop automatically takes a “snapshot” of a file when it’s opened. Use the History Brush to paint the original color back into the frog (or anything else that’s affected by the filter). Note that if you change the size of the original, or crop into it, you’ll have to make a new snapshot before you use AdvantEdge if you want to paint anything back into the image.
Now that the correct colors have been returned to her tattoo, it’s a simple matter to open another file to serve as the background, drag the transparent layer onto it, resize or reposition it if necessary, then flatten and save the image. See image 14.4.
I’m sure you can see the possibilities for this immediately. As long as the lighting and, especially, the camera angles in the studio shot and the background you wish to add to the image are reasonably well matched, your results will be golden. You no longer have to risk a crowd gathering around your sexy model as you’re trying to take advantage of an urban location in the middle of the day. See image 14.5.
Photoshop and a plug-in as potent as AdvantEdge can be an incredible combination. The key to creating successful images of things that don’t exist is to preplan. Think the shot through, thoroughly, and try to anticipate problems. Most importantly, try to picture the finished shot and figure out what you could do to make it more believable.
Some of you, gentle readers, may find this next image disturbing. I apologize if that’s the case (but thanks for the e-mails). Photography is an art form that investigates all aspects of life and of boundaries, documenting the staid while pushing the envelope of the new.
This image, meant to look as if the model had been standing in a lake of fire, utilized five strobes, fitted with grids and varying degrees of CTO (Color Temperature Orange) gels. CTO gels convert daylight-balanced light to incandescent-balanced light. They are available in strengths ranging from 1/8 to full strength. When the daylight color balance preset is selected on the camera, the sensor will record the light based on a 5200–5500K color temperature. Using light that’s closer to 3400K will make the light appear substantially warmer. Look closely and you’ll see that the model was mostly lit from below, to reinforce the look of light from fire. The model, of course, was unharmed in her greenscreen environment (although the final image did give her husband a bit of a jump). Two shots of a bonfire were combined in Photoshop to give the illusion of flames around her. Her figure was placed into the flames, masked in Photoshop, and given the appearance of dissolution into the flames. The water reflection was provided by a third-party Photoshop plug-in called “Flood” (www.flamingpear.com). See image 14.6.
Greenscreen or bluescreen work can be valuable to your studio’s bottom line. Those of you who do corporate portraiture may have a number of clients who prefer to have their employees photographed on location in the office. I’d suggest you only drag all the gear into their offices once, document the best locations for backgrounds, light them like portrait backgrounds, and create a file of those images. Hauling in and setting up lighting is a serious disruption to the general flow of an office. Consider the value to the clients if you only have to do that every few years, while you shoot their new personnel in the comfort of your studio, dropping in backgrounds as you go. Consider your value to the client if you’re the only photographer offering this kind of service. In essence, you’re creating client loyalty, something that’s often lacking in our highly competitive environment.
This is also a terrific way to approach stock photography because you can shoot whatever subjects you wish and place them into almost any environment. See image 14.7.Category: How-ToClick for more articles of: Christopher Grey
For many forms of portrait photography, greenscreen is a very inexpensive alternative to other methods, such as front projection. I’ve created numerous inexpensive, royalty-free backgrounds, many in varying degrees of focus, individually downloadable from www.christophergrey.com/backgrounds, for a small fee per piece. They are large files that can be used digitally or converted to film for front projection systems. This boudoir image (14.8) used one of the bedroom backgrounds included in those available downloads.
The biggest problem I’ve encountered with AdvantEdge is that it doesn’t like processed blond hair. It tends to turn it slightly magenta at the edges. This effect can be counteracted somewhat by placing a 5cc or 10cc magenta gel on the hair light (worthwhile if your clients are processed blond or not). The magenta from the gel will counterbalance the green that spills through the light hair but will not entirely eliminate the magenta fringe. I know that sounds slightly improbable, but it helps because it’s a complementary color to the green, adding the complement and reversing some of the green effect before the image is processed. One other problem is that if you duplicate the transparent layer you might add an extra line of density to one side of the subject.
One other problem I’ve had is with full-length figures. The green tends to reflect up onto the shiny leather of shoes. Of course, those reflections will “disappear” when the green is removed, and be replaced by the background. When the background is a solid color that’s usually not a problem, but it can be if the background is a complicated image. I usually have my subjects stand on a piece of white paper when I do full-length images, unless they are wearing white shoes. It’s easier to select and eliminate the white paper than it is to try and paint the shoes back in place. You may also have to add a “contact shadow,” the point where shoes contact the floor. If you don’t, your subject(s) may appear to float within whatever environment you place them.
These problems are not deal breakers, you’ll just need to play with the software to see if you like it. I have, and I do. Try other drop-out plug-ins too. You may find something else that’s perfect for you and your workflow, and “you” is the operative word.
There are several examples of greenscreen photography in upcoming chapters. I’ll point them out as we go along. You’ll see what I mean when I say it’s a valuable tool.