If you've ever found your eyes tiring by the end of a movie in your home theatre – and it has nothing to do with the writing, acting, or production – you may want to look into something like a bias light.
I knew about bias lights once but over the years, and through several changes in TV's over the years, I had forgotten just how much a bias light can improve one's enjoyment. Back then, I had (among other TV's) a 57-inch CRT rear projector, but while watching it I noticed that the picture would tend to dazzle my eyes, and not in a good way.
The result was that, instead of being amazed by my old Sony XBR's fine 1080i (yes, it was a while ago!) picture, I found my eyes would become fatigued, especially if I kept the room illumination minimized – which was and still is my standard operating procedure when watching video in my home theatre.
You could turn on more room lights to combat that tiring dazzle, but that creates other problems. For example, depending where the lights are, they could reflect onto the screen, which isn't a good thing because you lose contrast (and black levels – contrast – is one of the most important parameters in a quality picture). It could also introduce glare.
The bottom line is that by "washing out" your TV's picture with external lighting, you aren't getting the most out of your TV purchase. Sure, you can read while the TV's on, but that kind of defeats the purpose of watching something.
Back in that CRT rear projection days, the solution was to put a special fluorescent light behind the TV, in my case a product from a company called CinemaQuest, whose Ideal-Lume bias light was (as I reviewed it back in the early years of this millennium) "an unassuming little gadget the looks to all intents and purposes like a conventional fluorescent tube in a small bracket."
Judging from their website, they focus now more on industrial applications for bias lighting, but into that breach comes the folks at The Medialight, who offer a range of new, higher tech bias lights that use LED's, a strategy that makes perfect sense in this day and age.
The bias light raises the light levels in your viewing area, but without either shining a light toward your eyes or toward the screen itself, causing the problems outlined above. Basically, you get the benefits of the lighting without the drawbacks.
I mounted that earlier product onto the wall behind the projection TV, where it reflected its light output off the TV's back panel and onto the wall, causing a gently-illuminated frame around the TV (kind of like a halo), and this actually made the TV picture seem less "in my face" while also enhancing the picture quality, contrast and colour. In short, and to coin a phrase never used before, it made TV great again
Not just any light "bulb" would do, as I found out when I cheaped out after the original fluorescent bulb burned out. It's all about the colour temperature, as found in the "Kelvin Color Temperature Scale". Put simply, the lower the "K number," the warmer and more reddish the light will be, and the higher the K number is the "cooler and bluer" the light will be. Any bias light will help, as I found with my replacement fluorescent tube, but the ideal, er, lume – the colour temperature preferred by both TV manufacturers and content creators - is 6500K.
Obviously, the closer you can get to that magic figure, the better the bias light.
The Medialight folks offer a full range of LED bias lights, ranging from the $24.95 (US) Medialight Eclipse to the $89.95 (US) MediaLight Quad - and continuing right up to the $110 (US) MediaLight Mega 12v, the latter of which really isn't meant for consumer applications.
The company sent me three samples to try, including the Eclipse and the Quad, as well as the $49.95 US MediaLight 6500K Single 140 cm Strip. It was the latter that I attached to the rear panel of my 55-inch Panasonic 4K flat panel; the Quad is designed for wall-mounted TV's (mine's on a stand) and the Eclipse is designed more for smaller screens (42 inches and less) such as computer monitors (where it works very well).
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My, how technology has marched along! Not only do these products use LED's compared to fluorescent lamps, they mount very easily on the TV (well, you may have fun with wall-mounted screens), and they get their power via USB (except for the Mega) – which means you can just plug the sucker into many TV's and not take up a wall plug – and, some of them even come with a little remote control!
Setup on my Panasonic 55 inch 4K panel was a breeze, though this has turned out to bite me in the bum a bit: you just stick a couple of plastic hooks onto the back of your TV and string the LED strip through that - but the hooks keep falling off the back of my Panasonic, taking the Medialight with them. Some glue and/or cussing would correct this easily: the hooks come with their own peel-off stickum, but obviously it isn't enough to please my TV's rather roughly textured rear panel.
I think I might just nail it in place. That wouldn't damage the TV, would it?
The LED strip is longer than I need for that particular TV, but it's designed to be trimmed to the proper length – something I'm reluctant to do because I'll be trying the light with larger screens as I review them over time, so I might need that extra length. Besides, the excess hanging down doesn't bother me (out of sight, out of mind!) and, given my history of manual dexterity, if I try to trim it I'll probably break it.
All the Medialight, er, lights, claim a high-accuracy 6500K CCT (Correlated Colour Temperature), a Colour Rendering Index (CRI) of 90+ and, in case you can't power it via USB, an AC adapter is included. The products also come with a five-year limited warranty.
I didn't think I'd care about the little remote control/dimmer that came with the light, but as it turns out I love it. Not only do you not have to actually get up and turn the thing on (perish the thought!), you can change its intensity from 100 per cent to 10 per cent and monitor the results right from your viewing chair, which could save you getting up and going over to the TV several times (perish the thought).
After I messed around with the bias light's intensity settings in my viewing room I decided that 60 per cent is perfect for that installation.
Medialight's website has lots of information for folks looking to try bias light technology, and some of it is even written with a pretty good sense of humour. They also offer online chat/messaging and if you upload a picture of your installation they say they'll work with you to find a solution that fits your needs the best. Heck, they even have a section showing you how and where to cut the strip to customize it to your installation. And it looks easy enough for even an oaf like me to do it!
Okay, bias lights aren't going to cure cancer or make Hollowwood's product any better. But speaking from experience, they can definitely enhance your enjoyment and leave your eyes less tired when the show is over.
And it's a really cheap way to upgrade your home theatre!
Jim publishes TechnoFile Magazine. Jim is an affiliate with the Automobile Journalists Association of Canada and his careers have included journalist, technology retailer, video store pioneer, and syndicated columnist; he does a biweekly column on CBC Radio One’s The Business Network.
If you've ever found your eyes tiring by the end of a movie in your home theatre – and it has nothing to do with the writing, acting, or production – you may want to look into something like a bias light.
I knew about bias lights once but over the years, and through several changes in TV's over the years, I had forgotten just how much a bias light can improve one's enjoyment. Back then, I had (among other TV's) a 57-inch CRT rear projector, but while watching it I noticed that the picture would tend to dazzle my eyes, and not in a good way. 
