Getting Into Green Screen: Will It Work for You?
Backgrounds are a major expense for a photography studio. Over the years, I have worked with countless canvas, muslin, and various other backgrounds. One of the things I always longed for was the ability to change the background to match the theme or subject at will without taking so much time to arrange and light the new background choice.
One of the big developments in the digital imaging world is chroma-key technology. Chroma-key software has the ability to drop out specific colors, usually bright green or sometimes bright blue. Chroma-key in video has been around for many years, but does this technology now have a place in portrait photography as well?
I combined a chroma-key portrait with this background from EZ Backgrounds using PhotoKey4. I retouched blemishes and other minor details in Photoshop CS5 and then processed it with Imagenomic Portraiture, adjusted the contrast, and used Nik Color Efex Pro 3 to warm up the image and darken the corners. I sharpened the image with Nik Sharpener Pro and finally added a cement wall texture in the overlay blending mode of CS5. Overall processing took about 20 minutes. ©Kurt Robertson
Just as film photographers didn't switch to digital SLR cameras without experiencing workflow consequences, adding digital backgrounds to your studio will create new issues. How will you extract the subject from your images? How will you put the backgrounds into your images, and how good will the quality be? How much time can you afford to prepare your images? Most important, how will you present and sell the images?
Green Screen Wizard is a PC-only application with several versions available. Green Screen Wizard Pro 5.0 has many useful features for event photography, but our primary focus for this article is image presentation, green screen removal and image output.
Green Screen Wizard Pro 5.0 has a simple workflow for portrait studios. You click Load Foreground to load in your green screen photo and Load Background to preview your image. The Pick button allows you to preview the photo on multiple backgrounds at the same time (below), which will be valuable if you want to let clients choose their favorite background. It’s also useful for studio staff to be able to look at several options. You can also output just the subject with a transparent background as a .png file. Once you combine the subject with a background, the file will output with the background and subject combined (flattened).
Images ©Kurt Robertson
The image controls are easy to manage, and you can add shadows behind your subject to create a more realistic sense of depth in the image. You can also control the color of the foreground and background independently to create a better match the warmth or coolness of the background with the subject.
Green Screen Wizard Pro 5.0 yields good results with hair extraction by letting you indicate your subject’s hair color in the software. My experiments yielded good results with the default settings (below). “Hair is the thing that is the predominant worry among photographers,” according to Ken Colby, creator of Green Screen Wizard Pro 5.0. Bad color in the hair or jaggy edges will turn clients off quickly. In both applications, darker hair extracts better than blonde hair, though Green Screen Wizard performed slightly better with blondes.
Automated batch processing is also included. See the Green Screen Wizard website for a more thorough explanation of its batching tool.
All in all, Green Screen Wizard Pro 5.0 is a good product that worked well in my testing. If you are extracting to a transparent or light color background, you will occasionally need to adjust the settings for optimal extraction. But if you are inserting the subject on to a darker background it will generally produce very good results.
A free demo and information on the software is available at www.greenscreenwizard.com. Price ranges from $149.95 to $279.85 depending on the version and accessories you select.
PhotoKey 4 Pro, by FXhome, is a full-featured application for extracting foregrounds of chroma-key images, and it’s available in Windows and Mac compatible versions. PhotoKey 4 has a modern interface that I found easy to use (below). Images are loaded into PhotoKey 4 via the” Import” button in the “Import” tab. You may then load a background of your choice with the “Change” button in the “Background” area at the bottom of the screen. PhotoKey lacks a tool that will show you multiple backgrounds at once, which is a drawback if you elect to have clients select backgrounds, but sports a quick interface for changing between foreground images via arrow buttons at the bottom of the screen. Selecting the .png output setting and not loading a background behind your foreground will simply extract your subject from the background and save it as a .png file for compositing in Photoshop or some other image editing program.
Image ©Kurt Robertson
A unique feature is the “Matte View” button, which will show you the mask that PhotoKey 4 is creating to extract your image. The image above shows light fall-off from the top to the bottom of the image and a little green that is not being pulled out. I found this feature very useful in my tests. The extraction results were very good and did not require additional retouching to eliminate the green-screen when combining with a darker background (below). If you are extracting to just a transparent or light colored background you will occasionally need to adjust the settings for optimal extraction. A batch feature is included with hot folder ability to extract as you put images into the folder.
PhotoKey 4 has many sophisticated controls to blend your foreground and background into a seamless composite in most situations. A selection of filters are available to adjust brightness, contrast, and color controls to help match foreground and background.
PhotoKey 4 is priced at $299.00 For a free demo and more information go to www.fxhome.com/photokey-4-pro.
Other Sources of Digital Backgrounds
SIDEBAR: The Scene Machine, by Virtual Backgrounds
Virtual background technology is not limited to digital chroma-key. The Scene Machine system has been around for a while and is a proven commodity. “Backgrounds are an extremely powerful force for professional photographers, but unfortunately one that has been mostly overlooked by professional photographers,” says Dr. Henry Oles, creator of the Scene Machine system. Many of the industry’s leading photographers are using the system with great success.
The system consists of a background that is ultra-reflective and a special background projector that projects into a beamsplitter that mounts in front of your camera. A transparency is loaded into the background projector and is projected onto the beamsplitter. It then appears in your photograph wherever the special ultra-reflective background appears.
There are many advantages to this approach. Your images are finished from a background standpoint the moment they are shot, background and subject are captured simultaneously. You can see the image with the background when you look through the camera. Lining up your background and subject feels natural to the way most of us photograph our subjects. Subjects wearing green or blue do not experience issues with disappearing torsos that can happen with green screen technology. Chroma-key is prone to some cleanup correction issues with incorrect keying of the subject, and fine detail in the hair can be compromised if not done correctly. This can be corrected in Photoshop, but do you have the time in your workflow to do this? Basil Pecknyo, a longtime user of the system, says “the system is simply great. “You don’t have to go on location or relight and rearrange your studio very much, which increases the efficiency of photographing your subjects.”
The Scene Machine is not suitable for photographing with the intention of dropping out the background to create a collage or for commercial client who wants a transparent background. In that case chroma-key really can deliver. The other disadvantage is cost. Optical systems are more expensive. A typical green screen kit will run about $300 to $500 as long as you already own the lighting equipment. The Scene Machine ranges from $4,400 to $9,700 depending upon the model. All system sales include full tuition for a 3-day intensive training workshop held each month in Texas. You will also need to budget some money for background transparencies.
Photographers have to consider what you’re trying to achieve and how often you’ll use the technology that you choose to invest in. “Background Power,” by Dr. Henry Oles is an excellent resource for understanding how backgrounds can work for you. I was expecting a book about the Scene Machine, but it covers so much more. I highly recommend this book to any professional photographer.
For more information about the Scene Machine go to www.virtualbackgrounds.net.