Lumens vs Nits: How do they compare and why do they matter on big screens?

In the case of screens, this translates into the evaluation of different technical characteristics that previously escaped the knowledge of the general public. This time, from iLed México, we will talk about features that are not valued at the time of purchasing screens but that are crucial for their performance and that are related to the way in which light influences the quality of the projected image.

Candela, luminous flux and luminance

We know that when you hear the word candela, people dancing with a lot of flavor or that typical tropical enthusiasm of the people of Mexico and the rest of Latin America (exactly the same thing happens to us) come to mind, but this time we will refer to the physical meaning of this word. The candela is, in photometry, the unit that measures the luminous intensity and this is, in turn, the magnitude that consists of the amount of luminous flux emitted from a point at a solid angle.

For its part, the luminous flux is the magnitude of perceived illuminative power, that is, the power with which the human eye detects the different wavelengths (colors) that make up white light in its entire spectrum. Its unit of measurement is the lumen.

Maybe up to now all this information is seeming excessively technical, but we promise that everything will become more understandable as you progress in this reading, because you must know the meaning of these terms to understand the meaning of luminance, which is the central concept of this article.

In physics, luminance is the amount of light that flows in a specific direction on a well-defined surface. Since all the previously explained units of measurement correspond to the SI (International System of Units), we will take into account the square meter as a surface unit and, if the luminance implies quantity of light flowing, this flow must be calculated in candles. Thus, the unit that measures luminance is the candela per square meter (cd/m2), which is also known as nit.

Which unit is best used to evaluate the light of an advertising LED screen?

At iLed México we believe that it is often necessary to make the pertinent scientific definitions and then explain these notions so as not to be inaccurate. Having already done the technical definitions, we will now try to explain to you what the heck nits and lumens are.

Both units measure the luminous intensity from different factors, because while the nits refer to the light projected directly from the primary source, the lumens refer to the light reflected from a surface. The most commonly used example in scientific jargon is to think of nits as sunlight (a direct source) and lumens as moonlight (a reflective surface).

So, it can be established that one nit is approximately equivalent to 3.43 lumens and keeping this equivalence in mind will prevent you from being misled by large numbers in the specifications of the devices you are considering buying. You may find that for large, powerful displays (especially those intended for outdoor use) it is more practical to assess brightness in nits rather than lumens, since a nit measurement yields shorter numbers and therefore estimates. more accurate macro.

How does light influence the performance of giant LED screens?

When controlling the quality of the image projected by a conventional screen, we can resort to delicacies such as exposure, saturation, tint, color temperature, etc.; but the variable that has been and is so far the most important in this sense is brightness, since it is the main way in which light is present in the operation of a screen and on which most of its function depends. graphic quality. The brightness is, then, the main brightness control on the screens.

However, if on a domestic screen the brightness can determine whether what is projected is appreciated well or badly, on giant screens for advertising purposes it is crucial due to the macro level of definition that the message they communicate requires, since the content reproduced on a screen with insufficient brightness will hardly reach to be deciphered by the public no matter how gigantic the screen is.

Here is another of the great advantages of LED technology on screens, because even when they are used with maximum brightness, their graphic content is still fully visible. Therefore, they are the best option when it comes to outdoor advertising.

Choosing the correct number of nits

As we have already pointed out on other occasions, choosing screens with specifications that far exceed our requirements can be as detrimental as choosing one that does not satisfy them, and the case of brightness is no exception.

Screens with LED panel technology produce a brightness well above that of other technologies, however, we know as screens have greater brightness potential they are much more expensive. Also, a higher brightness value produces higher electricity consumption and that affects your operating costs. Therefore, it is important that you select the screen that most accurately meets your technical demands, this will prevent you from investing extra money.

In iLed México we are guided by a basic criteria of nits that depends on the place and the conditions with which each screen that is requested will interact. A conventional domestic LED television must have between 300 and 500 nits of luminous intensity so that its graphic content can be appreciated with sufficient definition in the most common conditions that exist inside the home, in such a way that, for a giant LED screen designed for interiors can transmit content with sufficient lighting, this must be a minimum of 1,500 nits, a value that can be raised to 3,000 nits to satisfy the most frequent large requirements; and up to 4,500 nits when the screen will inevitably face the sun directly.

Too often, many vendors mislead their customers by recommending 4,500+ nit indoor displays and complementing their sales pitch with the fact that they are weather tolerant displays. The reality is that the presence or absence of weather protection structures makes no difference to the luminous capacity of LED screens and furthermore, exceeding a sufficient nit value can result in an uncomfortable and even aggressive experience for the eyes of users. the spectators.

In the case of giant outdoor LED screens, 3,000 nits of luminosity can be effective, however we recommend that you choose those with 5,500 nits or more, as these guarantee very good graphic quality regardless of the light conditions that prevail in your environment.

Logically, one of the first concerns that arise when purchasing a giant outdoor LED screen is the energy consumption that it will have due to the great luminous capacity that it requires and the expenses that are generated from there. Fortunately, currently many of these screens incorporate a sensor into their structure that controls the brightness of the LED panels according to the light variations of the place where they are mainly due to time and weather. The engineering of this mechanism consists mainly of a photoreceptor that is stored in a completely waterproof container, so it is protected from outside environmental conditions. This sensor makes brightness control fully automatic and produces benefits in three ways: it produces substantial savings by reducing costs for energy consumption and consumable wear directly related to the lighting system, it considerably optimizes the time that must be dedicated to it to the operation of the screen and ensures the highest quality in the images (both static and video) that it reproduces, by always having the appropriate brightness level for the best appreciation by the viewers who are reached by your advertising message.

Another brightness control mechanism is the programmable remote system, through which different brightness settings can be assigned to the screen associated with a schedule. Their downside, of course, is that they don't respond to unexpected ambient light changes in the environment, instead keeping the default settings at all times.

In conclusion

If you want to measure the brightness of a screen, it is better to be guided by the nits because they indicate the amount of light flow from the direct source and not from an indirect one like lumens do. Also, nits return smaller numbers than lumens, which prevents you from creating a false expectation from a large number.

Choose the screen whose specifications are closest to what you need, since exceeding your requirements will mainly affect your finances.