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Shooting with green or blue screens is a huge challenge - especially for budget movie makers without access to a professional studio. Reflecmedia thinks it has the answer with ChromaFlex
Chromakeying is the process whereby coloured areas of a video frame are identified as transparent, allowing images or footage to be composited in their place. The technique is used to great effect in cinema, where actors are placed in hostile or impossible environments, but it´s also used in everyday television - providing a topical backdrop for newsreaders or a satellite picture for weather forecasters. These actors and TV presenters are shot against solid blue or green backgrounds - the colours are chosen because there´s no blue or green in human skin tones. But shooting with blue screens or green screens can be a logistical nightmare - particularly for creative dramatic projects.
For a chromakey effect to work well, the coloured background must be correctly exposed and evenly lit. Lighting the subject must then be done in a way that doesn´t affect the lighting of the screen, and additional care must be taken to ensure that no green or blue is bounced back from the screen onto the subjects. TV shows, music promos and commercial features shoot much of their chromakey in studios with carefully controlled lighting - often lighting huge green panels from behind. That´s great if you´ve got the budget, but little use for those of us slumming it with small crews, tiny budgets and temporary locations.
Reflecmedia´s solution for high-quality chromakey on the run uses a circular ring light that surrounds the camcorder´s lens, and a screen made of millions of tiny glass beads that reflect light in the same manner as cats´ eyes on roads. The ring is available in two sizes - large for professional camcorders and small for MiniDV - and two colours, blue or green. The background itself can be bought as loose fabric for hanging in a fixed studio or, as tested here, a collapsible screen.
The collapsible screen option (known as ChromaFlex), with small LiteRings in green and blue were put to work in a promotional video shoot for London-based punk band, Blocko. The shoot boasted a crew of only two - our reviewer, and Ray Liffen, the former BBC man who runs Intec Services - and took place in the drummer´s living room. The plan was simple - take various shots of each band member against the ChromaFlex screen, so that group shots could be composited during the edit, allowing cuts to be placed at different times for each band member.
Conclusion
Reflecmedia´s approach to chromakeying does a good job of removing some of the most fundamental problems of shooting with chromakey backgrounds, but it introduces a number of its own, too. The LiteRing causes problems when shooting glossy or reflective subjects, and can greatly annoy anyone required to make prolonged direct eye contact with the camcorder. The collapsible nature of the ChromaFlex screen is a huge bonus in terms of portability, but its strap design for stand-mounting definitely needs improvement.
This is a very expensive tool for occasional use, considering that simple green or blue Lastolite backgrounds can be bought for a tenth of the price of Reflecmedia´s setup. That puts it well out of reach of most hobbyists but, for those in the business of making instructional videos, corporate presentations, music videos or anything else using a lot of chromakey effects, ChromaFlex could be worth every penny. |
