Kitplus Magazine

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ACQUISITION How full is your Spectrum? by Ian Muir C olour tuneable (Bi-Colour) LED based lamps are now increasingly commonplace in the world of Film and Broadcast. Their capacity to provide a choice of colour temperatures, usually in the realms of 3200K to 5600K, can be extremely useful. This is particularly beneficial when working in environments where setup time is at a premium, and a light source is required that matches the available ambient light. The issue that often makes this approach problematic, is the design of the Bi-Colour fixture, and how it achieves its colour tuneable output. In most designs it is the simple technical expedient of having two colours of LED within the fixture, one set at 3200K, and the other 5600K. Colour mixing is facilitated by simply intensifying one set of LEDs, and dimming the other. This can provide a light source which matches the ambient; however the rudimentary spectrum is such that other aberrations can be introduced such as a Green or Magenta spike. To provide a clean image therefore with colour that renders well on camera, requires the further gelling of the source to correct the colour mismatch, which in turn can diminish its output, and therefore effectiveness. Historically this has been the lighting cameraman’s lot, particularly when working in environments where the ambient is another discontinuous light source, such as fluorescent tubes in the ceiling in an office. Carrying a good selection of correction, and the ability to decide what is easiest and quickest to correct has become very much part of the skillset. Whilst this can be considered very much part of the craft, it is dependent on having the required resources to hand, to say nothing of the time to implement a good setup. Help could be at hand however with the availability of better quality LED based colour tuneable sources, that have a “fuller” spectrum and are suitably portable. (From top left clockwise) Fiilex Q500-AC Unit, Fiilex P100, P360EX, P180E. Fiilex are as yet a relatively unknown (in the UK at least), range of colour tuneable hard sources, which utilise more than just two colours of LED to produce output between 3000K and 5600K. The LED chip incorporates a range of colours to produce a spectrum which has significantly less peaks and troughs in its resulting spectral curve. Immediately the output, which is a much closer emulation of a traditional tungsten source, reduces the likelihood of variation with natural light at a range of colour temperatures. Packaged as small Fresnel type fixtures, they can be powered from a battery, accepting an input voltage range from 12-24 Volts DC (via D-Tap). Output depending on the lensing option selected is approximately equivalent to a 350 Watt traditional source. The range of accessories available is also impressive, including two options for softening the output, an acrylic diffuser and a more traditional fabric based soft box. Barn doors are also available and can be used with two additional lensing options, one of which is full blown 5” glass Fresnel, which provides huge illuminance at a point considering the lamp’s power draw, with some spot flood capability. There is also a DMX capability that facilitates control of fixtures from a lighting desk. To complete the fixture line-up as a fully portable option, a range of hard case based kits are available, which group the fixtures into various configurations, including stands etc. The kits provide an easy option for most users, although building up a bespoke kit is still possible to suit personal taste. The full range of fixtures is distributed exclusively in the UK through A.C. Entertainment Technologies ( They can be seen demonstrated on their stand at this year’s BVE (stand number E20). Full details can also be found at 56 | KITPLUS - TV-BAY MAGAZINE: ISSUE 98 FEBRUARY 2015