Bias Lightning – dramatically improves screen viewing experience in the dark
Published on March 16, 2012 by mehigh, in Ergonomics
After reading all the positive reviews about bias lightning, I thought to give it a try… so I started off with the theory.
The basics that you need are the following:
- a light source with cold natural light (ideal is to have a temperature of 6500K)
- the light source to be powerful enough such that the reflected amount of light would be at least 10% the maximum light the screen can produce (under normal viewing conditions, not talking about dynamic contrasts or other such gimmicks)
- a neutral gray or white wall behind the screen (I didn’t have the luxury to get this, but we’ll get to that a bit later)
- patience to set it all up and do a bit of math
I found my screen to emit 130 cd/m2 under the settings I use it (THX).
I’ve computed the surface of my screen (42′ 10:9) – 93cm (width) * 52.3cm (height) ~ 0.48 m2.
130 cd / m2 * 0.48 m2 = 62.4 cd
Most light sources (like LEDs) have their power measured in lumen. And since 1 cd = 12.57 lumen, we get to a computed 784 lumen emitted by my screen.
Then we get the amount of light required to bounce off the surface behind the screen to be of at least 10% of 784 lumen, which is ~79 lumen.
Since I don’t have a 100% reflective surface, I assume about 50% of the light is reflected, which means I would need a light source of at least 160 lumen.
In order to obtain a better spread light, the best choice would be to have an array of LEDs going around the perimeter of the screen, in the back.
On my particular setup I required 3 meters of LED band.
There are two options for the LEDs:
- SMD 3528 (cheaper, emit a lower amount of light, best for bias lightning if you have a neutral colored background – they come in single colors)
- SMD 5050 (or the so called RGB LEDs, have a higher light output, in the 30 leds / meter setup they emit around 250 lumen / meter, while in the 60 leds / meter denser array most emit around 500 lumen / meter)
To make a paralel of the amount of light with the regular light bulbs – an ‘old-school’ 100 Watts incandescent light-bulb emits about 1400 lumen)
I’ve went with a 3m stripe of SMD 5050 RGB leds, with a density of 30 leds per meter, and although that would add up to 750 lumens (which is way too much), the controller allowed 10 steps of lower / increase the light emitted. (down to 10% of the maximum light output).
Setting it all up
I’ve powered it with a 5A, 12V power adapter (capable of powering up to 10 meters of 5050 LEDs).
I used an RGB Led controller which had an infrared remote capable to store color / intensity preferences.
The LED stripe had an adhesive tape, which I glued to the back of the screen.
Indeed, as per my calculations going for 20%-30% of their power source (which would go to 150 – 225 lumen) was indeed providing the best experience.
To take out some of the pink in the background, I setup the LEDs to go with a bit of a colder color to compansate, and I am really pleased with the end result:
Disclaimer: This is not a professional advice, I had gotten to the conclusions listed in this post after browsing the web and reading various people opinions on forums. If you want the best quality out of your setup, you should hire a professional.
If you had made a similar setup, or are going to, let me know your thoughts by commenting below. Do share what’s your experience with bias lightning.