Virtual Studios

Author: Dennis Lennie

Published 1st November 2008


Traditionally virtual studios have been extremely expensive to equip due to the amount of technology required just to make the studio work. Besides the standard studio cameras and lighting, sophisticated additional technology is required to provide feedback from lenses, pan and tilt heads and dollies, to seamlessly synchronise foreground and background sources. Each camera, its lens and associated ancillaries must be carefully calibrated to maintain tracking between the sources.
Having acquired and aligned all this kit, the studio itself needs specialist setting up to achieve the optimum results. The blue or green screen itself can be produced in a number of ways; traditionally this would be a coloured curtain, a specially built and painted set or the studio walls simply just painted. However in every case, for best results the background has to be lit both brightly and evenly. This calls for vast arrays of cyclorama lighting all the way around the studio, sometimes at the top and bottom and even either side of the curtain. Due to both the large amount of light reflected off the background and the positions of the overhead lighting, it is necessary to place the talent some distance from the background to avoid spill and to avoid the background lighting interfering with the light for the talent.
Thus a large amount of expensive studio real estate becomes redundant. The extra lighting involved can also stretch the capacity of air conditioning and power supply systems. The non-production time required rigging lights and painting for this type of show puts pressure on already compressed studio schedules. Most of us will have at some time been faced with a situation that no matter how much pre-production planning went on, the costume turns out to be the same as the chosen key colour. Repainting, re-hanging and relighting time cuts deeply into any programme makers contingency fund.
It could be argued that these problems are well within the capacity of existing traditional studios as they were built to cope with these extremes. However, the economic and temporal constraints of modern programme making, combined with the fact that more non-purpose built spaces are being used as studios, means that normal chroma key production will stretch the resources of both a programme makers budget and his premises.
New styles of studio production often occur in converted offices or some other building not originally designed for TV production. Rarely is there enough floor space available, nor is power or heating and ventilation adequate for the energy demands of the production. However, modern cameras are very sensitive and developments in cool lighting mean that day-to-day production is usually very successful. Chroma key in these environments is a different story as the extra lighting, space and power required by a chroma key rig, may preclude its use in these situations.
As in all areas of TV production, technological development equips the modern programme maker with a new set of tools to enable production to continue within these constraints. One such development is that of retro reflective materials such as Reflecmedia`s Chromatte and Chromaflex products. Developed in collaboration with research teams at the BBC, Reflecmedia have produced a cloth that contains millions of minute retro reflective beads, randomly applied to the cloths surface providing it with some exceptional properties. Illumination is achieved using a ring of light emitting diodes that are housed in a circular enclosure that secures to the front of the camera lens usually via its filter thread. The 5-watt output of the LiteRing is all that is required to illuminate the curtain. The LEDs are chosen for their narrow spectral bandwidth and are dimmable via a simple LiteRing controller. Due to the nature of LED’s, little change in colour temperature occurs when they are dimmed. Therefore, the colour returned from the cloth remains constant throughout a wide intensity range. Coverage of a large studio drape is not a problem as the LiteRing is attached to the lens, so when the camera pans or tilts the LiteRing illuminates the portion of the curtain the camera is framed on.
Any residual coloured light that hits the subject is so low in intensity that under studio lighting conditions it becomes insignificant. Also, because the intensity of the reflected light is low, there is no over the shoulder spill problems associated with traditional chroma key, The talent can be placed flat up against the curtain if required. The random orientation of the beads means that the cloth does not need to be stretched nor flattened and can be also used to cover foreground objects that need to be eliminated. The lack of separation between talent and cloth, the low power requirement and ease of setup are all advantages to a small studio wanting to move to virtual studio production in non-standard premises. Finally, if your talent turns up in a blue suit that matches the background colour, you simply and quickly change the LiteRing on the camera and your blue screen studio becomes a green one.

Related Articles

Related News

Related Videos

© KitPlus (tv-bay limited). All trademarks recognised. Reproduction of this content is strictly prohibited without written consent.