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Defining High Definition

Rich Carlson is a technical manager for Kodak's Entertainment Imaging Division. He works with Kodak customers to provide technical support, in addition to assisting with new product development. He is based at Kodak's New York City office. Here Carlson addresses some of the most frequently asked questions about the choice of media and the role that the evolution of motion imaging technologies plays in creating commercials for high-definition television:

How about film technology?

There have also been exciting advances in film equipment, including the highly mobile ARRI 235 camera, the small, lightweight IKONOSKOP A-Cam, and the new ARRI Master Prime lenses made by ZEISS. However, the most dramatic advances in film technology have been in the media itself. The new generation of KODAK VISION2 Color Negative Film incorporates a quantum leap forward in film technology, giving cinematographers even more latitude and flexibility on set, saving time and money. Kodak offers an extensive palette of emulsions with specialized imaging characteristics that gives cinematographers incredible flexibility under just about any circumstance.

What about the future?
Won't high definition continue to improve?

Film is format- and future-proof. Film's superior image quality and inherent high resolution mean your images will be ready for the next new broadcast format. Film is also the most reliable archival medium. There have been more than 75 video formats since the introduction of videotape in the late 1950s.

What is HD?

High definition (HD) refers to technology that captures, manipulates or displays images using more picture information than previous systems. The term can apply to cameras, postproduction equipment and processes, or display devices. The first high-definition digital video cameras were introduced in 1987.

How many households have HDTV sets?

A recent study by In-Stat, a tech market research firm, estimates that the rate of growth of HDTV households will continue to be strong over the next several years, and by 2009, HDTV households worldwide are forecast to reach 52 million. Another study from Kagan Research estimates that by 2015, HD households will reach 110 million. The firm estimates that more HD programming and lower HDTV costs will drive the number of HD households to nearly 97 million, or 82 percent, by 2010.

Does high-definition television require images to be captured with digital video cameras?

No. In fact, 35 mm film is by far the best capture medium or content destined for HD display. The higher resolution and better picture quality of high-definition televisions make film's superiority as a capture medium even more apparent. The vast majority of dramatic content seen on highdefinition television today originated on film. When clients only have 30 seconds to make an impression, film is the obvious choice.

Are many commercials produced and aired in HD format?

Four cutting-edge cinematographers-Bill Bennett, ASC, Allen Daviau, ASC, Wally Pfister, ASC and Paul Cameron-recently addressed these issues at a seminar in Los Angeles. They have cumulatively compiled over 1,500 TV commercial credits. Although they have photographed HD spots using film, very few of those spots actually aired in HD due to the perception in the advertising industry that many households cannot receive or view HD broadcasts. However, all four cinematographers recommend finishing TV commercials in HD format even if they are slated to air in standard definition, since HD is the highest quality broadcast and display format.

How does shooting on film for HD affect production?

Cinematographer Bill Bennett says it takes about 60 seconds to replace the 4:3 ground glass in the film camera with a 16:9 ground glass. Everything else during production is the same. In post, the facility just flips a switch on the telecine to convert it from standard to high definition. It's that easy, and it's already happening with many television series and movies that are shot on film and posted in high-definition video format.

Why do filmmakers prefer film for images destined to be displayed in HD?

Film works well with high-definition display for the same reasons it worked well with standard definition display. Film offers greater creative and practical flexibility on the set and during postproduction due to its much greater dynamic range. More important, film has a unique dreamlike quality that evokes a different emotional response from audiences. Audiences subliminally associate the film look with quality. Advances in postproduction and display technology mean that more of what is captured on film can be delivered to the postproduction stages, adding creative flexibility and resulting in a richer experience for the viewer. Why post in HD format if the spot isn't going to air that way? Because there are nuances in colors, contrast, and other details recorded on the film negative that are rendered more effectively with an HD telecine transfer, which you then convert to standard definition video images. Cinematographers and directors believe that makes a difference.

Why aren't more film-originated TV spots posted and aired inHD?

The most common answer to that question is the higher cost of postproduction in HD resolution. Postproduction costs in HD are more expensive than standard definition because of the higher cost of the equipment. Facilities charge a premium for HD work. However, the end product of HD post is suitable for either HDTV or SDTV broadcast, so there is an advantage to doing the post in HD.

If a spot will post and air in HD, why not use an HD digital video camera? Can anyone tell the difference?

The audience may or may not see the difference on a conscious level, but chances are they will feel it on a subliminal level. That's why directors and cinematographers refer to film as an organic medium that has a dream-like quality.

Is it possible to explain why in reasonably simple language?  

Film and digital are fundamentally different mediums. Film sees and records images very much like the human eye. There are millions of randomly scattered silver halide crystals embedded in every layer of each frame of 35 mm film. When light comes through the lens and hits the film, it causes a chemical reaction that forms latent images that are amplified when the negative is processed. When light comes through the lens of a digital camera it strikes a CCD sensor containing a rigid grid of pixels. That light is translated into analog voltage, which is amplified and converted into numerical values. The images have a different look. Film also requires a certain threshold in exposure to light before it begins forming latent images. That gives cinematographers more flexibility to manipulate light in ways that create subtleties in textures, contrast, and colors that are part of their visual vocabulary. This is part of what makes film more of an interpretive form of expression.

Are there other differences between film and digital video?

It's a common assumption that an image recorded on a frame of 35 mm color negative film can be scanned and converted to digital data at 4K resolution. However, testing conducted by our scientists last year indicated that when you scan an image recorded on a 35 mm frame it can be converted to an 8 to 9K digital picture file. Film also has an incomparable dynamic range, which enables cinematographers to record more nuanced colors and tones in scenes with both dark shadows and bright highlights. The most advanced digital cameras can dig deep into the darkest shadows, but they tend to blow out details in highlights.

Is film more expensive than shooting with HD video cameras?

There are benefits to using each medium. The greater latitude inherent in the film negative allows cinematographers to work much more quickly on set, when production time is very expensive. When shooting with an HD video camera, "what you see is what you get." The result is much more time spent on set carefully previewing the images, and then thoroughly tweaking every detail of light and shadow, because there is very limited ability to change later in the post process. That "preview and tweak" time becomes very expensive. However, directors and cinematographers look at film and digital cameras as tools. We suggest that you ask for their opinion about the choice of media when you are planning to produce a spot.

Aren't digital cameras improving?

There have been dramatic advances in digital cameras. That's the good news, and it is also the bad news, since obsolete hardware is a hidden cost of progress.