What Bias Lighting Is and Why You Should Be Using It

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The Sterling Creations team

A Dan Thompson contribution
What Bias Lighting Is and Why You Should Be Using It
(How To Geeks April 28 2015)
There’s a good chance you’ve been watching television and working at your
computer for years in a way that fatigues your eyes,
increases your chance of headaches, and overall decreases your enjoyment and
comfort. Read on as we show you how to create a
comfortable and high contrast viewing experience with bias lighting.
What Is Bias Lighting and What Are the Benefits?
Before we delve into what bias lighting is and why you’ll benefit enormously
from implementing it in your work space and living
room alike, we need to look at the mechanics of the human eye to truly
understand why bias lighting isn’t just a showy trick akin to
putting superfluous lights on a street rod but a very useful technique that
not only increases viewing comfort but image quality at
the same time.
Why Screens Strain Our Eyes
The most important thing to understand, in regard to watching a screen and
the importance of bias lighting, is that your eyes work
on a system of averages. When you look at something, whether that something
is car headlights in the distance, a pretty
landscape, or a television screen, pupils dilate to regulate how much light
enters your eyes. The degree of dilation is triggered by
the entire scene your eye is taking in and not by the single brightest point
of light within that scene.
When we watch television or use a computer work station in a completely dark
or significantly darkened room we create a less-
than-ideal viewing situation wherein our eyes are staring very intently at a
small window of very bright light that is floating in a sea
of darkness. Despite the fact that we accurately perceive the screen to be
very bright in relationship to the rest of the scene our
eyes take in, our eyes attempt to adjust based on the average brightness
across the entire field of view and not the average
brightness of the screen (or, conversely, the dimmer off-screen area). As a
result our eyes become rapidly fatigued and with
extended exposure we experience dry eyes, general discomfort, watery eyes,
and even tension headaches radiating out from the
temple area. In worst case scenarios with extended exposure some people
experience ocular migraines, extreme headaches that
result from intense eye strain.
Fortunately, despite the fact that your mother might have insisted watching
too much TV or TV with the lights off would make you
go blind, the effects of such eye strain are temporary and within less than
a day of exposure the symptoms of dry eyes and fatigue
should resolve themselves. That doesn’t mean you need to endure it every
time you use your workstation or watch a movie on your
beautiful new HDTV; let’s take a look at how bia lights can relieve the
strain and then how you can get started using them.
How Bias Lights Relieve Strain
So how do we avoid our inevitable exposure to bright light in the form of TV
viewing and workstation time frying our poor eyes? The
key is to increase the general luminance in the room without introducing
problems that arise from just indiscriminately flipping all
the lights on.
Visiting the link directly below will whow a 3D mockup of a pretty typical
living room setup to illustrate how common lighting
configurations are problematic for screen viewing (although this mockup is
centered on an HDTV, the same lighting problems
apply to workstations too).
In your typical living room/workspace you have ceiling lights, floor lamps,
and table lamps, all of which are typically located either
above (as in the case of ceiling lights) or located in front of the screen
at roughly the same height as the viewer’s head like the
table and floor lamp seen in the image at the site mentioned above.
While turning on these lights while viewing the television does in fact
mitigate the issue of the bright screen framed against a very
dim room it introduces a whole new host of problems. Lighting that is to the
side or behind the viewer projects light onto the
viewing surface and decreases contrast, introduces glare and haze to the
image, and creates its own kind of eyestrain as a result.
It may not be as intense as the kind of eyestrain you get staring bleary
eyed at a bright TV in the dark, but it’s eye strain
nonetheless and it makes the picture look worse.
Bias lighting is the lighting that is placed behind the screen you are
viewing such that it raises the ambient light levels in the
viewing area without directly shining light toward the viewer nor shining
light past the viewer toward the screen (where it could
create reflections and other viewing problems). In the above mentioned room
mockup, this means the light should be placed in the
triangle behind the television set so that the light radiates outwards and
in a diffuse manner around the bright window created by
the screen.
Because the light originates outside of the sightline of the viewer and is
not in a direct path to reflect onto the screen, you get all
the benefits of increased luminance in the room without the problems of
glare or light shining directly from the source into your
The Additional Benefits of Bias Lighting
If you still need some convincing that extends beyond saving your poor eyes
from fatigue, then consider the benefits of bias
lighting beyond simply relieving your eyes. In addition to warding off eye
fatigue there are two great benefits. First, the additional
indirect lighting provided by the bias lighting increases the contrast of
the on-screen image.
Refer to the optical illusion image one can check out at this link:
to see the effect made apparent. The bar that stretches across the center of
the image is one constant shade of gray (RGB: 142,
142, 142) but it appears to be lighter in on the dark side of the gradient
and darker on the light side of the gradient. This illusion,
known as the simultaneous contrast illusion, readily illustrates how our
eyes perceive gray to be darker and richer when seen
against a lighter background and more washed out when seen against a dark
background. Illuminate the wall behind your screen
and the same contrast illusion takes effect: the grays and blacks on your
screen will appear richer and the contrast will seem
stronger between them and the surrounding area.
Related to that previous trick, many people adjust the values for brightness
and contrast to higher levels in order to get the
intensity of color and black contrast they desire. If the environment you’re
watching the screen in already helps boost the contrast
and create a better looking image on the screen then you can turn the
brightness back down. Not only will your eyes thank you
because the screen isn’t shining at your face like a headlamp, but you’ll
extend the life of the backlight mechanism in your HDTV
or monitor.
Eye fatigue reduction, better looking images, and a longer life for your
monitor’s backlight? What’s not to love about bias lighting?
Let’s take a look at how to set it up so you don’t have to live another day
with screen-induced eyestrain.
How to Select and Setup Bias Lighting
At this point you’re probably thinking “okay, okay, you’ve got me. Bias
lighting sounds great, and I want it. Just tell me how much it
costs so I can get over the shock.” Fortunately for you, it’s really cheap
to implement a perfectly functional bias lighting system.
Don’t get us wrong, there are very pricey ways to go about doing it (such as
purchasing a Philips TV equipped with their custom
color-shifting bias lighting Ambilight system) but there’s absolutely no
need to incur such expenses when there are plenty of
inexpensive alternatives.
First, let’s break down what makes for a good bias light and why then lets
look at some economical ways to implement both DIY
and off-the-shelf solutions.
Selecting a Bias Light
The most important thing to consider when selecting a bias light for your
television (aside from the physical consideration as to
whether the said light style will actually fit behind the screen) is the
color temperature.
Light bulbs have a color temperature listed using the Kelvin Color
Temperature Scale. The lower the number the warmer and more
red the light; the higher the number the cooler and more blue the light.
Candle flames are 1,900K and are very warm and cast a
very reddish/yellow light. Standard incandescent light bulbs are
approximately 2,800K and are still quite warm. “Cool White” or
“Daylight” bulbs have color temperatures ranging from 5,000-6,500K.
While any bias lighting is better than no bias lighting as far as eye strain
is concerned, if you want bias lighting that not only
relieves your eye strain but actually makes the content you’re viewing look
better you’ll need the right bulb. To that end, you want a
bulb temperature that is as close as possible (if not identical) to the
reference point used in the industry that both manufactures
the screens you’re looking at as well as creates content for said screens
and that’s 6500K.
The bulbs (be they CFL or LED) inside your HDTV or monitor are calibrated to
6500K, the film and digital video shot is color
corrected to have a 6500K white reference point, and the editing suites
where content is edited and worked on have 6500K bias
lights. Regardless of whether you use a fluorescent tube light, a strip of
LEDs, or an incandescent light bulb, you want one with as
close to a 6500K color temperature as you can get if your goal is to
maximize the quality of the on-screen image.
This immediately rules out the majority of lighting we use around our homes
as there is a distinct consumer preference for warmer
light. What makes for a homey and warm feeling in your abode, however, makes
for a poor bias light for your screen.
In addition to selecting a light source that is approximately 6500K color
temperature, if you’re dead set on getting the absolute best
picture possible you may wish to also look at the Color Rendering Index
(CRI) of the light bulb. This number is rarely listed on
bulbs intended for household use but with some careful digging (or by
purchasing bulbs intended for hobby or commercial
applications where the CRI is important such as high-end saltwater fish
keeping) you can find the CRI. A CRI of 90 out of 100 or
above is the minimum you should aim for if you’re looking for maximum color
clarity on your HDTV or computer monitor. This is
definitely the province of people looking for an absolute picture perfect
experience as opposed to simply relieving eyestrain,
however, so unless you’re building the ultimate home theater setup or you’re
looking to break into video editing you needn’t stress
about getting a perfect CRI-rated bulb. A quality bulb with a 6500K color
temperature is more than enough for just about everyone.
Simple DIY Solutions
All of the solutions we’ll highlight in this guide are DIY in that you have
to purchase and install them yourself but the distinguishing
characteristic here is that you’re cobbling together a solution out of
lighting not intended for bias light use.
When we first started searching for a solution to our marathon gaming and
Netflix sessions leaving us with burning watery eyes we
opted to immediately deploy DIY solutions based on materials we had laying
around the house first. Better to see if the bias
lighting even helped than to spend a bunch of money on a fruitless project.
If your television set or monitor is separated from the wall by some
distance, our HDTV set and stand are cocked at a forty-five
degree angle in the corner of our living room, for example, it’s very easy
to place a regular lamp assembly behind the screen.
In our case we grabbed
a simple and cheap metal shop lamp
with a clamp attachment and then popped a daylight temperature
LED bulb into it. The whole assembly shines light up into the space behind
the large HDTV and diffuses it along the walls. This is
a great solution for people with large sets because it uses the wall as a
diffuser, requires only one bulb, and provides total
coverage for even 65? screens and larger.
While we’re perfectly happy with the setup (as it cost us nothing because we
had the parts on hand and would only have cost us
around $18 if we bought the parts new) if we wanted to upgrade it while
still keeping the project fairly inexpensive and DIY, we
could purchase a daylight fluorescent bulb intended for reef aquariums and
lizard keeping. A good bulb with 6500K color
temperature and a 90+ CRI rating runs about $25, add in a simple lamp
assembly to mount it in might run you another $20. For
under $50 you can have as close to what they use in professional studios
without shelling out $$$ for the experience.
Again, in the use-what-you-have category, we rigged up our multi-monitor
stand with some IKEA Dioder LED puck lights we had
laying around. A simple set of four pucks and a little power brick assembly
will run you around $25 at IKEA. We’re including this
not because the Dioder line has perfect color temperature (they don’t) but
to highlight what you can accomplish just using
materials you have laying around and that even lights a bit warmer than what
you’d want in a perfect studio setting or optimized
home theater can still work well.
Although we originally intended to upgrade the bias lighting on both the
HDTV and workstation after establishing that bias lighting
relieved our eyestrain and other issues (which it absolutely did) we’ve
found our simple DIY solutions have worked well enough
that any major upgrades or enhanced DIY projects are now more a matter of
cosmetics and perfectionism than necessity.
Commercial Bias Lighting Solutions
If you’re just looking for a solution that you can buy, plug in, and go
without worrying about matching bulbs or purchasing your
own lamp assemblies or the like there are more than a few solutions
available. The cheapest and easiest solution we recommend
to anyone who asks is the
Antec Bias Lighting for HDTV kit
You can order or see one here:
It’s $26 out the door, 6500K color temperature, it includes everything you
need right in the kit, and the LED strip is both bright and
easy to trim (the strip has pre-marked points where you can safely cut it to
remove extra LEDs which makes it easy to use on
HDTVs and monitors big and small).
The entire assembly is USB powered so you can, if you wish, drive it off
your HDTV set’s USB port so the bias lighting
automatically turns on with the set. Overall it’s the most compact and easy
to install solution we’ve come across that doesn’t
require soldering or a bulkier DIY solution with a larger lamp assembly.
Another solution (and the one which should be considered the gold standard
for bias lighting) is to
buy a bias light kit directly from
, the company that produces bias lights for professionals.
You can pick up a their Ideal-Lume Standard light, intended for HDTVs and
monitors that aren’t mounted right to the wall, for $65
and their Ideal-Lume Panelight, in tended for wall-mounted installations,
for $95. Such a setup will run you a little more than a DIY
arrangement or other commercial solutions but for the price you get a custom
bulb with 6500K color temperature, a 90+ CRI rating,
and an lamp assembly designed for easy installation and adjustment.
Ultimately it’s so easy to use bias lighting to banish eyestrain, headaches,
dry eyes, and other symptoms caused by bright-TV-in-
dark-room viewing that it truly makes no sense not to do so. The only thing
standing between a comfortable viewing experience
with high contrast, crisp colors, and no eyestrain is a light bulb and a
little bit of installation work.

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