TUTORIAL - GREENSCREEN OBJECT MOVIE by Pat St. Clair
To shoot the IQTVRA cap object movie, I used a homemade turntable, a Kodak DCS 330 professional digital camera with a Nikon 60mm macro lens, five White Lightning strobes, a greenscreen fabric background, and a compositing plug-in called Primatte.
The TURNTABLE: The turntable was the cheapest lazy-susan at the local home improvement store (Chase Pitkin). I found the center, drilled a hole and screwed in a light weight dowel.
CAUTION: It's worth all the time it takes to find the exact center of the turntable and to mount the dowel so it is precisely perpendicular.
I marked 10 degree increments on the turntable and put four marks on the baseboard (equivalent to north, south, east & west).
HAT I steamed the hat, as it arrived very wrinkled. I stuffed it with newspaper to give it shape and mounted it on the dowel in such a way that it was centered and level.
Lighting: THERE ARE TWO SEPARATE "LAYERS" TO THIS LIGHTING... THE BACKGROUND AND THE HAT. (The lighting ratio between these two layers is important and can affect the ease of the compositing process . . . it’s best to run a quick test prior to shooting the entire object movie). When possible, these two layers should be far enough apart so as not to contaminate each other (i.e., keeping a saturated green light on the background and NOT on the hat; and keeping white light on the hat more than the background). I used soft boxes on lighting for the hat to keep the light somewhat contained and more directional than umbrellas would provide.
WORKFLOW - I shot one frame every ten degrees of rotation for 36 frames in all. This allows me to build a larger, smoother object movie for CD use (using all 36 shots) and a smaller leaner object movie for web use (using 18 shots). - I rendered RAW files to tiffs using Kodak software - I used the naming convention "01", "02", "03", etc. - I created and used a PhotoShop action to: - apply a curve to adjust tonality, - fine tune color using the color balance command, - slightly sharpen as well as reduce noise using Quantum Mechanic Pro, - resize to a desired resolution, - add a 4th channel (to save a mask ... part of Primatte 1.0 workflow). - I selected a graphic background and used Primatte 1.0 (compositing plug-in for Photoshop) to combine the greenscreened hat shots with the selected graphic background. Primatte can also save the mask it created as part of the compositing process.
COMMENT: There are many possibilities for compositing. I find Primatte is intuitive and easy to use, but doesn’t contain as many expert user options as some others. The more complex software solutions for compositing may offer a higher level of control, but are more expensive and have a steeper learning curve. Again, this is a purely personal decision. I find myself looking at the others, but coming back to Primatte. - I applied a drop shadow to each frame within PhotoShop. I select the mask created in Primatte, inverse the mask, then use the airbrush tool to draw the mask. Again, there are many ways to approach a drop shadow if you decide you want to use one. - I saved each frame flattened and used QTVRAS to create the object movies.
About the author: Pat St. Clair has a bachelor’s degree in marketing from Miami University (O), 1971, and a bachelor’s degree in professional photography from the Rochester Institute of Technology, 1979; he has been photographing commercially since 1978. St. Clair serves a corporate clientele that includes agencies of all sizes as well as direct corporate clients such as Eastman Kodak Company, Palm, Xerox, Hewlett-Packard, 3Com, DaimlerChrysler, ExxonMobil, Microwave Data Systems and more. He was an early adopter of digital technology and has worked with Eastman Kodak Company on digital capture projects and digital image quality issues for the last eleven years. He has worked with QuickTime VR since 1994, is a charter member of the IQTVRA (now the IVRPA), and was a speaker at the first four VR Summits in Boulder, CO, Washington, DC, Sedona, AZ and Savannah, GA. He is onboard to speak again at the 2006 VR Summit.
He owns and operates St. Clair Photo-Imaging in Rochester, NY. More about Pat St. Clair and his work can be found at St. Clair Photoimaging
The TURNTABLE: