Dynamic Development: Five things exhibitors need to know about HDR projection technology
Why are the colors, brightness and contrast of cinema projection so limited? It is a result of the lack of brightness and contrast available in today’s projection technology.
In the real world, there’s a vast spectrum of brightness. From the inky blacks of a moonless night to the cheerful yellow of a flower in sunlight, there is tremendous range from 0.001 to 14,700 nits. The term “nits” is used to define brightness, also known as candelas, per square meter (or cd/m2). For reference, typical TV content is only about 100 nits maximum. Today’s 2D cinema projection standard is about 48 nits (or 14 foot-lamberts as the cinema industry defines it), which is only a fraction of the range we see in the real world. Cinema projection standards have evolved little over the last 100 years, and were originally based on the capability of light sources and the heat tolerance of film.
With digital projection technology, laser illumination and high dynamic range (HDR), we can move beyond previous limitations to deliver a better image for the big screen. Here are five things exhibitors should know about HDR projection technology.
HDR Brings Greater Luminance to the Cinema:In its simplest terms, HDR imaging enables filmmakers to create a picture with a greater range of luminance (the range of light levels from the blackest of blacks to the brightest of whites that can be viewed on a screen). This is also called contrast ratio.
Not All HDR Is Created Equal:The contrast ratio that a projector can display determines how rich the image looks on the screen, and some projectors offer higher contrast-ratio capabilities than others. Projectors with a higher contrast ratio produce sharper-looking images, giving the perception that they have more resolution, which creates a more realistic-looking and impactful experience for the viewer.
Still, it’s important to understand that delivering a better image isn’t just about providing a wider range of brightness but also a wider range of available and displayable color. The ability to reproduce more and brighter colors also enhances the viewer experience. Dolby’s version of HDR imagery, Dolby Vision™, encompasses all the elements of higher luminance and more color range than previous display technologies have offered. The Dolby Vision projection system uses state-of-the-art optics and image processing to deliver high dynamic range with enhanced color technology. Filmmakers have praised this approach for its amazing contrast, high brightness and color range that more closely matches what the human eye can see. With Dolby Vision, the blacks are truly black, colors are vibrant, and the contrast ratio far exceeds that of any other image technology on the market today. The result is a richer, more detailed viewing experience that delivers strikingly vivid and realistic images that make viewers feel like they are in the movie’s world.
Equipping the Cinema for HDR Helps Deliver a Premium Experience:Projecting HDR images, particularly for large-screen applications such as the cinema, requires significantly more light or luminance than can easily be provided by conventional xenon lamps. Lasers provide a very efficient and stable light source, and are a key component for delivering HDR. Another required component is a projection head with an optical design that can take full advantage of the increased luminance, by not only providing brighter images onscreen but also lowering the black level to provide deeper blacks—delivering the very definition of HDR.
In order to project pristine HDR images, a great deal of attention must first be paid to the design of the cinema. Furthermore, light reflections from all surfaces in the room need to be taken into account, to minimize light reflecting from the screen and back to the screen. When the engineering and design teams at Dolby undertook the task of designing Dolby Cinema™, they kept all this in mind, optimizing the design for the function. This is why the vast majority of materials in the auditorium are designed and selected to control ambient and reflected light. The design uses black materials whenever possible and avoids bright or reflective elements (including ornate fixtures and lighting elements). Additionally, where possible, the Dolby Cinema design integrates an acoustically transparent fabric structure to cover the speakers on the walls and ceiling, to prevent light reflections from speakers and other interior components.
Dolby Vision is an integral part of Dolby Cinema, and we believe we have a system that not only greatly exceeds conventional digital projection systems, but also extends beyond the capabilities of film.
HDR Delivers a More Powerful 3D Experience: Beyond delivering a brighter, more colorful image, HDR (using laser illumination) can deliver a much better 3D experience to cinema audiences. The Dolby® 3D solution uses six primary laser (6P) light sources that are perfectly tuned to Dolby 3D glasses, eliminating the need to filter the light in the projector, making Dolby 3D the most efficient 3D system on the market. With 6P laser, Dolby can deliver 3D images at up to 14 foot-lamberts to the viewer’s eye (through the glasses). The result is 3D images that are dramatically brighter, with more color and with superior 3D separation and accuracy than any other 3D system currently available. For 2D images, the Dolby Vision system delivers up 31 foot-lamberts with very high contrast, which far exceeds other “ultra-bright” commercial cinema experiences.
HDR Gives Audiences More Detail: Today’s motion picture cameras, film or digital, capture much more dynamic range and color than moviegoers traditionally get to see. This is due to the limitations of current projection technologies, which require that content be altered to match display performance, dramatically reducing the range of colors, brightness and contrast. A true HDR color-grade, using the Dolby Vision workflow, creates a master that maintains more of the details and increased color that motion picture cameras can already capture. Now, for the first time, most of that detail and richness can be delivered to the big screen.
At Dolby, we have embraced the full capabilities of HDR by taking an ecosystem approach. Dolby Vision gives creative teams the freedom to use the full gamut of colors, peak highlights, greater brightness and amazing contrast, with the confidence that they will be reproduced faithfully on cinema screens featuring Dolby Vision.
To learn more about HDR, I encourage CinemaCon delegates to attend a special technology session, “HDR: The Next Frontier,” at the Colosseum at Caesars Palace in Las Vegas on Wednesday, April 22, at 12 noon.
Dolby Laboratories’ senior VP of cinema, Doug Darrow, will host the world’s first inside look and discussion on the benefits that HDR technology will bring to the creative aspect of storytelling. HDR movies coupled with immersive audio will deliver the ultimate moviegoing experience, pulling audiences deeper into the filmmakers’ stories than ever before. This session will showcase the creative benefits with demonstrations of content in both 2D and full-brightness 3D. Delegates will be able to see the future for themselves.