We spend many hours of the day and much of the night looking at screens that emit light. This includes a desktop computer, a mobile or tablet screen, and especially a TV screen, which has grown in size and brightness in recent years.
While CRT TVs of the 1990s ranged from 20 to 32 inches, modern LED screens range from 32 to 85 inches, or larger. The most modern TVs with organic diodes (OLED) or quantum dots (QLED) offer a high level of brightness and, above all, better contrast. That is, bright colors are brighter and blacks are blacker.
At the same time, an increasing number of TVs offer backlighting, that is, soft lights placed behind the TV screen to provide ambient light that is projected onto the wall or the surface behind it. The idea is to reduce eye strain during long viewing sessions, since, in theory, the contrast between a bright screen and a dark room can cause eye strain and eye fatigue. In addition, this lighting increases the perceived contrast on the screen, which looks sharper.
This technique can be as simple as placing a few simple LEDs or bulbs behind the screen, or in the case of what’s known as “biased lighting,” a series of colored lights that react to the colors displayed on the screen. screen. For example, if there is an image of a desert under a clear sky, the bottom of the screen will be lit with a sand-like orange tone, and the top will be lit with a bluish tone like the sky. The most advanced ones not only synchronize the tones of these colors, but also the intensity, so they will be brighter when the content on the screen is brighter and less when it is dimmer.
One of the pioneers of TV lighting is the manufacturer Philips, which introduced it in Ambilight models in 2002, and today it is a common feature on its TVs. Other manufacturers don’t offer this because Philips has a patent for this system, but there are still alternatives for those who want to put this type of lighting on their screens.
One of them is also offered by Philips. On the one hand, it is necessary to purchase Philips HUE series programmable LED light strips and, on the other hand, an interface called Hue Play HDMI, which is connected to the HDMI output of the TV to synchronize the colors of the lights. which will appear on the screen. The price of the set can exceed 500 euros.
Other manufacturers offer cheaper but less elegant solutions. For example, Govee offers a colorful LED light bar for placing behind the TV and a small camera that is placed on the screen for around 80 euros. The camera takes a picture and synchronizes the colors of the lights. The manufacturer Lytmi performs this synchronization without cameras, also via an HDMI port, for less than 200 euros.
The cost, in any case, can be significant if we want the colors to be synchronized with the image and much less if we just want an LED strip that lights up our screen with fixed colors and is connected to a USB port. The question is, is the investment justified by the benefits it provides?
There is evidence, although limited, that high contrast between bright and dark areas can cause eye strain. Most research in this area has focused on visual ergonomics and eye strain associated with screen use in general, rather than synchronized ambient light specifically. For example, it has been studied that the contrast between a bright screen and a dark environment causes more visual fatigue, and that reducing this discrepancy by brightening the environment or reducing screen brightness relieves fatigue. Visual fatigue is manifested by dry or watery eyes, general discomfort and even tension headaches that radiate from the temple area.
One could argue that turning on the lights in the room where we watch TV is enough. However, this leads to new problems. Side or back lighting casts light onto the viewing surface, reduces contrast, makes the image appear reflective and blurry, and as a result creates a peculiar eye strain. Ambient lighting, placed behind the screen, raises the ambient light level in the viewing area without directing light into your eyes or the screen itself.
In addition, the optical phenomenon is known, which means that when the screens are backlit, our brain perceives the image more sharply and with greater contrast. Just look at the following picture:
Although it may not seem like it, the gray bar in the center is one shade of gray. However, it appears darker on one side and lighter on the other due to the influence of the surrounding color. Similarly, if we illuminate the back wall with similar colors to the image, but at a lower intensity, we will see the image better. It’s like increasing the contrast in the TV settings, but without adjusting this setting.
If we want to place simple lighting behind the screen, the color temperature is important. Most TVs on the market have a white calibrated color temperature of 6500K, or bright white or “daylight”. Therefore, the LEDs we put behind must also have this temperature. The brightness should be 10% of the brightest white on the screen, something hard to measure, but we can calibrate it by eye if we put a white image and adjust the lights in parallel.
The ambient lighting systems mentioned above take this step away from us. Simply install the LED light strip on the back of the screen and the system dynamically adjusts both color and intensity. Some people on image forums claim that lighting can be distracting and distracting from what you’re seeing and change the perception of color if, for example, it’s a monitor you’re working with. On the other hand, many others find that ambient light improves their viewing experience and eye strain. In any case, it is worth considering that bright lighting before bedtime can interfere with the quality of sleep.
Source: El Diario
