In order to understand the concept of brightness, it is essential to understand the metrics that are used to measure brightness of any light source, including LED light strips. The metrics used are either Lumens or Lux and the difference between these two metrics is that while Lumens typically measures total visible light emitted by a given light source into the environment surrounding the light source, Lux measures the total light that falls on a given surface which provides a measurement for estimating how well-lit the specific surface area is.
The correlation between these metrics is 1 Lux = to 1 Lumen per square meter (1 lux = 1 lumen/m²). In summary lumens present the total brightness of the light source and lux describes the level of light intensity that falls on a specific surface. These measurements are suited for incandescent bulbs and fluorescent lamps where the brightness is highly dependent on wattage rating.
The brightness of LED strips on the other hand is determined in metric lumens and it must be noted here that different LED strips function at different levels of efficiency and therefore the same wattage for a one-meter LED strip may produce different levels of brightness. This concept applies to both indoor LED light strips and as well as waterproof LED light strips.
LED strip brightness described in lumens per meter should generally deliver at minimum of approximately 1500 lumens for every meter of LED strips which would be equivalent to the amount of light or brightness that would be delivered by a one-foot conventional T8 fluorescent light.
The brightness of LED strip is dependent on three primary factors which are the output and efficiency of the LED emitters, the concentration of LEDs on each meter and the power-draw of each one-meter strip. For those looking to buy LED strip lights, it is recommended that they check for brightness specification on the packaging without which, it is not advisable to buy.
Some low-cost waterproof LED strips may claim high brightness despite the low concentration of emitters on each meter; such strips could potentially result in the LEDs to overload to the point that they tend to fail prematurely.
LED emitters may be presented with code types (e.g. 2835, 3528 or 5050), however, the type of emitter should not be made a priority when it comes to brightness, as the concentration of LEDs and the power-draw per meter play a bigger role in brightness. When it comes to LED density it is also important to note the pitch of the strip (distance between LEDs) which will determine if there will hotspots or dark areas would be visible between the LED emitters.
Ideal concentration of LEDs would be 120 LEDs per meter or more have been observed to provide optimal lighting effect. Of all the components on an LED strip, the light emitters are the costliest component, therefore differences in LED density or concentrations should be taken into account when comparisons are made between LED strip prices.
