More lumens = more light = better product?
WRONG! And this is why
Any lighting manufacturer will normally state how many lumens their product produces; essentially being how bright it is. Indeed lighting legislation worldwide requires manufacturers to give customers this information.
The dictionary definition of Lumens (symbol: lm) is the International System of Units (SI) derived unit of luminous flux, equal to the amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candela – in simple terms the light power emitted by a light source.
A product can produce on paper a lot of lumens, for example a laser which is very bright but has a very tightly controlled beam. This is great if you want to illuminate 1 square mm at 5km distance, but if you want to use it for other applications then it would be totally useless.
It is therefore important not only to look at how many lumens (how much light) a product produces but also how much light arrives on a working area – this is measured in lux.
The dictionary definition of Lux (symbol: lx) is the International System of Units (SI) derived unit of illuminance, measuring luminous flux per unit area. It is the amount of illumination provided when one lumen is evenly distributed over an area of one square metre – in simple terms how much light is hitting a surface over a square metre area.
Ritelite calls this “Useful light”
As lumens describe only the light emitted from the light source in any direction and also do not consider any losses in light due to lenses, diffusers etc, lumens are not relevant in terms of describing the level of illumination arriving on a work area of a given size and distance from the light source.
It is far more important to understand how much useful light (lux) a product gives a user; indeed international standards for safe illumination of working areas are only specified in lux.
Understanding how much lux a product illuminates, and thus how much light actually hits the ground to light up the area where the user is working or playing sport, or carrying out any other work activity, is therefore crucial for customers to identify the best product to meet their lighting requirements.