Eyes are not only extraordinarily beautiful, but fascinating to study.
When it comes to light intensity, the iris (the colored part of the eye) controls how much light enters the eye through the pupil (the black circle at the center of the eye) in order to protect the retina (the light-sensitive organ at the back of the eye). This mechanism helps to see better at night and protect against the glare of full direct sunlight.
At BubblyNet we take your eyes seriously and we strive to interpret light as they do.
On the chart below, you can see how the Perceived Lightness decreases as the Measured Lightness is reduced.
When dimming a luminaire to 50% intensity, it is then perceived at an intensity of 70%.
When dimming the luminaire to 1% intensity, the perception is 10%. The luminaire needs to be dimmed down to 0.01% to obtain a perception of 1%.
This is why, the accuracy of the dimming level is particularly important at very low levels and why BubblyNet uses Perceived Lightness as a scale.
To be exact, this is the formula used on all BubblyNet dimming:
The Perceived Lightness of a light (L) is the square root of the Measured Lightness (Y):
Where L is the Perceived Lightness and Y is the Measured Lightness (from 0 to 65535).
Note: The scientific community’s understanding of the exact relationship between the L and Y variables has changed over time. For a detailed history, see “The Basis of Physical Photometry” from the International Commission of Illumination (CIE). The CIE works with the International Organization for Standardization (ISO) to define global standards for various types of illumination. The organization’s published illumination standards and research publications are available on the CIE website.
As an example, when you dim down your BubblyNet controlled luminaire to 3%, your perception of the lightness is as well 3% while, to obtain the desired result, the measured electricity running through the luminaire is only 0.09%.
It is the replication of the human eye experience as when in the middle of the night, as the pupil is at maximum aperture, a very tiny light looks extremely bright.
Most dimmers and control systems on the market have a Measured Lightness dimming scale that is way off when compared to the daily user experience. This is why we always recommend our clients to opt for Perceived Lightness dimming scales whatever the brand or solution.