4K Production Poses Challenges

While 3-D has been catching fire, another digital format has been mostly languishing: 4K. That is changing, as AMC Theaters has struck a deal to convert the entire chain -- more than 4,500 screens -- to 4K-capable Sony projectors. Faster computers and cheaper storage are making 4K more practical all the time, and now that there will actually be thousands of 4K screens, the format is a more viable option.

Film moving through a projector wobbles enough to slightly blur the image on the screen, and 2K d-cinema is just a bit sharper than 1080p HDTV. But 4K is different.

"4K digital projection is so sharp and so rock-steady you really see every detail," says Kim Libreri, visual effects supervisor at Industrial Light & Magic. "It doesn't look like movies you've seen in the past. It's got this hyper-real quality."

For now, the format requires some trade-offs. First, it means eschewing 3-D. Today's d-cinema projectors can't process data fast enough to show a left and right eye at 4K. Also, shooting options are limited. The Red camera can shoot in 4K, but most 4K capture happens on good old-fashioned film. Going back and forth from film to digital is slower and more expensive at 4K, whether it's scanning film for digital intermediate or digital visual effects, or printing out to film at the end of post.

Also, in digital intermediate, "We're color-correcting 2K proxies" (i.e., smaller versions of the huge 4K files), says Erik Rogers, senior DI producer at Company3 in Santa Monica. "You can't get real-time playback (in 4K)."

Digital vfx in 4K can be challenging, but some companies already work in that format part of the time. Sony is committed to 4K from cameras to projectors, and Sony Pictures Imageworks has long worked at higher resolution for many shots, even when it only needs to deliver in 2K.

SPI's chief technical officer Rob Bredow notes that, even so, only certain elements in a vfx shot have to be made at 4K -- "anything with a high degree of detail that's in focus, (like) leaves on a tree or a person's face."

Today, 4K is a way to future-proof content. Eventually, it's likely there will be projectors that show 3-D in full 4K resolution so audiences -- and distributors -- get the benefits of both.

"It's clear that things are going there," Bredow says. "The fact we're building 4K theaters speaks to the fact that there's a demand for that level of quality."

By David S. Cohen, Variety