May 3, 2005
Bringing a graphic novel to film: It’s an act of courage if you succeed, an act of stupidity if you fail. Fortunately for directors Robert Rodriguez and Frank Miller (who originated the graphic novel), the hard, stark look of “Sin City” puts this film in the courage category, in no small part due to Rodriguez’ decision to shoot “Sin City” in high-definition video. And not just any old high definition -- “Sin City” was shot digitally with Sony’s HDC-F950 camera in 4:4:4 -- full bandwidth, uncompressed video—on HDCAM SR videotape.
This said, many of the benefits that HD video brought to the production aren’t obvious on screen. The reason: Like a good special effect, much of what HD video gave to “Sin City” does not stand out and scream for attention. Instead, the increased resolution simply enhanced and reinforced the raw look that Rodriguez and Miller were aiming for in their drive to bring the Sin City graphic novels to life.
“HD video really suited the way in which Robert wanted to shoot this film,” explains “Sin City” camera operator Jimmy Lindsey, who shot the film with Rodriguez. “When you’re shooting a graphic novel on film, every element has to faithfully re-create that comic book look: The gun not only has to be in the right place but also captured with the right angle and perspective. With HD video, we were able to take the shots and then check them immediately [on HD monitors]. We were able to get every image right.”
”Sin City” Tech
Sony’s HDC-F950 camera was the real “unseen angel” on the “Sin City” set. “What makes the HDC-F950 different from all other Sony HD cameras is its ability to shoot and record uncompressed 10-bit 4:4:4 RGB digital 24p,” says Yasu Mikami, Sony Electronics’ marketing manager for TV and motion picture production. “To do this, we have linked the HDC-F950’s three CCDs with a fiber optic transport system capable of moving up to 3GB of image data per second. This information is then stored on our HDCAM SR format videotape, whose 440Mb/s transfer rate is three times faster than standard HDCAM.”
“Better yet, HDCAM SR’s higher capacity means that images as large as 1920x1080 pixels can be recorded, rather than HDCAM’s 1440x1080,” Mikami adds. “This allows you to capture the full 4:4:4 RGB HD data provided by the camera head.”
Footage on HDCAM SR tapes was ingested using Sony’s SRW-5000 HD digital videocassette recorder connected to a SpectSoft RaveHD DDR via a Dual Link SDI connection (consisting of two HD-SDI cables, each running 1.485Gb/s), with an AJA Xena HD22A SDI card inside the RaveHD.
“When you are shooting a film like ‘Sin City,’ visual details are everything,” says Lindsey. “You need the kind of crisp and sharp details that the HDC-F950 captures.”
The capture of crisp details was also enabled by Rodriguez’ lens choices. Optics for the HDC-F950 were supplied from Fujinon’s family of cine-style HD zoom lenses. Specifically, Rodriguez used the Fujinon E Series HAe5x6 (6-30mm) and HAe10x10 (10-100mm) zoom lenses. Fujinon’s E Series lenses are designed for distortion-free optics, minimal focus breathing and reduced chromatic aberration.
“One of the reasons Rodriguez selected these lenses was to avoid the time lost from switching prime [fixed length] lenses for different shots,” says Dave Waddell, Fujinon’s marketing manager. “Meanwhile, the larger diameter of these lenses helps keep the f-stop value from falling off when you change the focal length. You need the highest resolution images possible when you’re dealing with effects, and the E Series gives you that.”
On the Set
In general, “’Sin City’ was a two-camera show, with Robert and I both operating wide and tight frames,” says Lindsey. “When only one camera worked, he usually did the actor-intensive stuff and I usually did the dolly and crane shots. Of course, when you are working with Robert Rodriguez, there are no rules. However, this doesn’t mean that we shot without planning. Each angle was planned out by Robert and served a specific purpose for the edit.”
To convincingly create “Sin City’s” gritty graphics and comic book-style visual effects, Rodriguez shot much of the film against greenscreen. He then relied on the speed and immediacy of HD video not just to capture what was being staged in short order but also to allow for accurate blocking and continuity checks on the fly.
As a result, Rodriguez specified that his HDC-F950s be equipped with LCD HD monitors rather than conventional film-style eyepieces. Having these monitors helped ensure accurate focusing and framing, Lindsey says. “Had we used NTSC monitors, we would not have seen the same level of detail about lighting and focus that is provided on HD displays.”
Using monitors also made it easier for Lindsey and his assistant to work together on complex shots. “We could both see clearly and in detail what was coming through the lens thanks to the monitor,” he says. “You just can’t do this when you’re using an eyepiece.”
As mentioned earlier, HD video’s immediacy made instant playback possible, allowing for accurate shot lineups and continuity checks. The ability to see what had just been shot also let Rodriguez craft every sequence of “Sin City” deliberately and methodically, just as Sin City artist Frank Miller crafts the Sin City graphic novels when he draws them.
One thing that wasn’t done on the set, however, was the rendering of “Sin City’s” video in stark black and white. “We shot the movie in full color in order to provide Robert with maximum flexibility during post,” Lindsey says. “If the color’s in the video, you can always take it out later. But the last thing we wanted was to send him into post with black-and-white footage, only for him to decide that he really wanted some color in a specific sequence.”
Greenscreen Compositing
Again, the benefits of the HDC-F950’s 4:4:4 video capture are not necessarily apparent in what turned out to be a nearly monochromatic movie. The filmmakers sought the greater color depth afforded by the 4:4:4 format to aid the extensive chroma keying process in this film, which relied heavily on greenscreen compositing techniques.
It is much easier for compositors to isolate and pull keys from Dual Link (4:4:4) source footage than Single Link (4:2:2) because of the greater proportion of chroma sampling in the encoding.
Most digital video cameras convert captured video from the RGB color format to YCbCr color format and also downsample the chroma portions. Downsampling allows compression of the video signal and separates the luma signal (Y), which is perceptually (to the human eye) more important, from the chroma signal (Cb and Cr), perceptually less important and therefore able to be represented at a lower resolution. (The human eye is more sensitive to brightness information than color—among colors, by the way, our eyes are most sensitive to the color green. Engineers recognized this fact when devising video codecs by representing green more prominently in video signals. Chroma keying with digital video is therefore often executed against a greenscreen.)
The 4:1:1 encoding of DV and DVCPRO samples the chroma at 1/4 the luma. In other words, luminance is sampled for each pixel, while Cb and Cr are sampled at every fourth pixel. In 4:2:2 video, such as DVCPRO50 and Digital Betacam, the chroma is sampled at half the luma, which is acceptable for viewing because of the human visual system’s greater sensitivity to luminance detail. The 4:2:2 encoding is less suitable, however, for compositing work; computer processors do not share the human eye’s preference for brightness over color. When chroma is represented at half the level of luma information, adjacent pixels will share color information, making it difficult for compositors to get a clean key edge. In full bandwidth 4:4:4 encoding, all channels are sampled equally and may be selected during keying with much greater accuracy.
Visual Effects
The noir drama “Sin City,” which visually emulates the stark black-and-white style of Frank Miller’s graphic novel series, is divided into three chapters named for titles in the comic series. Rodriguez chose to allow three visual effects companies (The Orphanage, CaféFX and Hybride Technologies) to handle the effects in each chapter, with one chapter per facility. Rodriguez also allowed each house to come up with its own techniques to bring Miller’s graphic style to the screen.
The Orphanage’s visual effects and animation division completed nearly 600 visual effects shots for “That Yellow Bastard,” the third chapter in the film. Visual effects supervisor and company partner Stu Maschwitz headed up The Orphanage team. More than 70 visual effects artists completed the work, which included full digital environments, hard surface modeling and animation, advanced compositing and CG snow and water effects.
“Sin City is hands down my favorite graphic novel series,” says Maschwitz. “For me, there’s nothing cooler than having the chance to help Robert bring Frank Miller’s vision to the screen in all its black-and-white glory.”
The Orphanage used a setup similar to the film’s production team for dailies, finals and to transfer clips from RaveHD (with its AJA Xena HD22A SDI card) back to HDCAM SR tape for delivery of shots to Rodriguez. According to Jason Howard of SpectSoft, “The shots would be rendered into linear 10-bit RGB DPX and transferred to the storage array connected to the RaveHD system. From that point, [The Orphanage team] would use RaveHD to play back each clip to check it on a calibrated monitor in full RGB gamut. If it made the grade, they would use the RaveHD box to print the frames back to tape [via an insert edit].”
Canadian firm Hybride Technologies tackled 600 shots on “Hard Goodbye,” the first chapter in “Sin City,” and Santa Monica’s CaféFX provided 600 effects shots for middle story, “Big Fat Kill.”
The team at CaféFX had the opportunity to display their improvisational skills on the project. “We were basically handed the footage and told, ‘Okay, create Sin City,’” says Visual Effects Producer Edward Irastorza. “The panels of the comic were our storyboards. In fact, the only reference we were given was a copy of the book.
“To make it more challenging, as we were beginning our work, Robert was on another shoot for a month and a half and out of contact, so the feedback turnaround was difficult. We just trusted our research and instincts. Thankfully, he loved it.”
Not only does “Sin City” the film emulate the panels and storylines of the novels, it emulates the original graphic style. “All of the footage was filmed in color and needed to be changed to black and white,” adds Irastorza. “And, by black and white, I don’t mean grey, which is probably what you’re used to seeing when watching a black-and-white movie. I mean either black or white, with very little to no grey in between. The same went for all of the environments we created—which is exactly how everything is drawn in the novels—to essentially create a moving comic. And, like the book, we added select splashes of color. All the characters have eye color, Dwight’s shoes are red, and so forth. The book was our guide.”
Directors Rodriguez and Miller relied on DLP Cinema projectors to ensure rich and consistent color in the movie. The hyper-realistic black and white and desaturated color look of “Sin City” was achieved through the use of a DLP Cinema projector at EFILM, where the color-correction process took place. The film was color-timed for both film and digital projection. “With a one-to-one ratio between what is done and what is projected, changes can be viewed immediately, rather than waiting for days in the traditional photochemical, film-based process of color timing,” says Rodriguez. “The DLP Cinema projector was key as both a valuable timesaver and creative tool in the digital workflow.”
HD Video as a Way of Life
With a film career stretching back to the 1991 short “Bedhead,” followed by hits such as the “Spy Kids” trilogy and “Once Upon a Time in Mexico,” Robert Rodriguez is no stranger to 35mm film. However, don’t expect him to move back to that medium anytime soon, if ever.
“HD video is perfect for Robert’s style of filmmaking: It keeps up with his speed and precision,” explains Lindsey. “It’s great to see him knowing exactly what’s being captured and being able to make changes on the fly as he sees fit. Frankly, I can’t imagine him shooting on film again.”
.
|