Designing Room Lighting For VideoconferencingThe new Design Guide from IESNA is the closest thing pro AV has to an international standard for videoconferencing lighting design.Source: PRO AV MagazinePublication date: December 1, 2005By Tim Cape, CTS-DWhile the ultimate goal in videoconferencing is good interactivity between near- and far-end rooms, one common lighting design problem can be summed up in a question thats remained constant throughout the evolution of videoconferencing technology: How can you provide good, comfortable lighting to optimize the camera and video codec operation in an architectural environment rather than in a studio? Although its a fairly simple question, the answer can be quite complicated.There must be some light in the room of the space youre designing just for the camera to produce an image, but making that image look good while maintaining a good projected video image can be easier said than done. On top of just getting the camera to produce a decent image, you also have to be concerned about what the codec will do to that image (particularly at low bit rates), putting more constraints on not just the lighting design but also the interior design of the room itself once again going beyond the tenets of a basic AV system.Up until now, AV professionals havent had much consistent guidance on videoconferencing room lighting design, but the new design guide, offered by the Illuminating Engineering Society of North America (IESNA), gives them an authoritative place to start.The new design guide In development since 2002, the “Videoconferencing Lighting Design Guide,” DG-17-05, is now available for purchase through the IESNA website (www.iesna.org). It includes a wide range of recommended criteria and general recommendations for approaches to lighting for videoconferencing facilities. Its specifically oriented toward small- to mid-sized videoconferencing rooms with a single camera axis (from displays to seated participants). It doesnt specifically cover dual-axis rooms that include a presenter near the displays or larger facilities, though much of the criteria can be applied to this wider range of rooms.The Guide is intended to some extent for designers both with and without a background in lighting design.The old design problem Before answering the question presented above about how to optimize the camera and video codec operation in an architectural environment, you must understand several basic and sometimes conflicting requirements. And its not just about the luminaires that emit the light, its about the room, too. The primary tasks in terms of lighting are:Light the participants for good video. This involves limiting the variation in light level enough to allow the camera to reproduce the full range of light and shadow in the picture. At the same time, there needs to be enough variation in the picture to keep it from looking “flat” with no shadow or depth.Light the room to complement the participants. This means paying attention to the lighting for the walls, floor, and ceiling areas that might be in the camera view.Coordinate the room finishes from the standpoint of color, contrast, and pattern, and how they relate to the people in the picture. This also involves consideration of the type of finish, and how it may affect the image picked up by the camera and transmitted to the remote site. For example, reflective, or specular, finishes such as chrome can create problems for the camera by creating an excessively bright spot in the image.Sometimes there are more particular constraints placed on the lighting system when special cameras or higher than normal color rendering are needed for specialized applications like retail, fashion, and some military environments. However, the basics above apply to any videoconference room and are discussed in the GuideThe fundamentals To create an environment that works well for videoconferencing, designers must address some fundamental lighting parameters. For those in pro AV, this may mean becoming familiar with at least the basic lighting terms youll encounter in a lighting design project. While the AV designer may be qualified to be the lighting designer in some cases, its more likely that he or she will be providing criteria to a lighting or electrical consultant who will then design the lighting under a separate scope of work. In either case, the AV designer needs at least some basic lighting knowledge.To begin working with lighting, some basic lighting terms should be understood. Some of the typical terms used in discussing and designing lighting systems are related to those for projection and display technologies.Illuminance is the light level incident on a surface or plane from a source or sources. Its expressed in lux (lumens per square meter the preferred unit of measure) or footcandles (fc, lumens per square foot the more obsolete unit). One footcandle equals 10.76 lux. Its us