In an exclusive Q&A, Andrew Robinson, managing director of leading screen manufacturer Harkness Screens, discusses the role of screens in the transition to digital projection, and the options open to exhibitors who want to maximize the impact of the new wave of 3D movies.

What costs should be taken into account when considering the conversion to digital cinema?
Both total cost of acquisition and total cost of ownership should be discussed when considering the conversion to digital cinema.
With total cost of acquisition, the upfront expenditures for projector and screen are interrelated; considering the screen at the same time as the projector can allow the exhibitor to select a smaller projector, thus saving considerable money. Savings are possible even on HVAC design due to a reduction in heat output enabled by a smaller projector.

With total cost of ownership (which is too often ignored), ongoing operating costs in terms of lamp cost/replacements, lamp/HVAC power consumption, and maintenance are considerable but can be managed by smart upfront design. A gain screen can help the operator avoid considerable ongoing operating expense in each of these areas. As the conversion to 3D is ongoing and the 3D slate continues to rise, there is still considerable debate about the right mix of 3D and 2D auditoriums. Some exhibitors have chosen to “future-proof” their estate by deploying more 3D-capable screens than they think they’ll need because the screens are flexible enough to also show 2D content.

What screen consideration should be taken into account when converting to digital?
Using higher-gain screens will increase reflected light levels, and thus your potential to use smaller lamps. Using a higher-gain screen can save enough that you’ll recover the costs of the screen purchase in one to two years. If a smaller projector can be used, the savings will usually offset the entire cost of the screen.

If you plan to show digital 3D, other screen considerations come into play. For starters, all digital 3D technologies lose a significant amount of the light available in 2D mode due to the filters and 3D glasses required to create separate left and right-eye images. This means larger lamps and high-gain screens are required to achieve an acceptably bright image. Also, depending on the 3D technology used, a specific type of screen may be required. 3D technologies using polarized light (such as RealD) require a “silver” screen to maintain the light polarization as it is reflected from the screen back to the audience. This technology will not work with the usual “white” cinema screen. Silver screens can be used satisfactorily to play 2D content, but you’ll need to reduce your lamp power; otherwise, the screen in 2D mode will be too bright.

Other 3D technologies such as XpanD or Dolby 3D use white screens, but they still need high gain as the light losses are similar. High-gain screens achieve a greater brightness because a greater share of the light falling on the screen is directed back to your audience. Matte white screens (with a typical gain of 1) scatter light in all directions, wasting much of it toward your walls and ceilings. However, there is a consequence of the increased directionality of gain screens: The screen will appear less bright when viewed from extreme angles. This effect can be minimized by curving the screen frame, recommended on higher-gain screens.

What are some factors that affect light outputs of digital-cinema projectors and how can you achieve adequate light level?
Light outputs of digital-cinema projectors are affected by a number of factors that can prevent the screen from achieving its recommended brightness level. One such factor is how the digital projector is set up to project different film formats (including the possible use of an anamorphic lens). The lamp’s life point is also important, as at 50% of life, typically 25% of the original light output is lost. In extreme circumstances, overall light losses can be as high as 50%. Different models of projectors are offered with different lamp size options. Lamps in all digital projectors are short-arc, high-pressure xenons that usually have bigger price tags and shorter warranty lives than their equivalent 35mm projection lamps.

Adequate light-level planning is critical to ensure high-quality presentation when considering digital-cinema conversion. Adequate light level can be achieved via a combination of projector power, lamp power and screen gain. Light distribution is more uniform with digital projectors than with film, which enables higher-gain screens to provide a better experience. Harkness Screens’ Digital Screen Selector can help ensure cinema operators are maximizing their investment when converting to digital.

How is Harkness Screens helping cinema operators looking to convert to digital?
To assist cinema operators looking to convert to digital, Harkness recently rolled out its Digital Screen Selector. The Digital Screen Selector was created to be a technology-agnostic guide for theatre operators seeking to maximize their digital-cinema investment when consulting with projector, lamp and 3D technology providers. The Digital Screen Selector can reduce operating costs for 2D and optimize light levels for both 2D and 3D. In a few easy steps, the DSS can show how to save thousands annually on a per-screen basis.

Available through the Harkness website, www.harkness-screens.com, the Digital Screen Selector features a user-friendly interface with no software download required and uses SMPTE standards and vendor data to compare different operating scenarios in providing cost-effective, environmentally friendly Harkness Perlux® screen solutions.

Harkness’ Perlux gain screens reduce digital-cinema projector brightness requirements significantly relative to matte white screens, enabling the use of smaller lamps that are cheaper, last longer and consume less power, roughly halving operating costs—which is good for not only the operator, but the environment as well. For new builds and digital retrofits, a Perlux screen can pay for itself in under a year. For existing digital installations, a Perlux replacement screen can pay for itself in just two years. Gain screens can also be considered a “green” investment because they lead to less CO2 (lower power needs) and fewer lamps to recycle or scrap. This can help exhibitors meet building guidelines for energy efficiency, and can even contribute to LEED certification by the U.S. Green Building Council.