Like the title said, why does blue light seem dimmer than yellow light even when they’re the same intensity?
In: Physics
Human eyes are most sensitive in the yellow-green range. It’s the color of leaves and the predominant frequency in sunlight.
“The sensitivity of the human eye in fact varies according to the wavelengths, λ, of the light emitted. The sensitivity of the human eye is maximal at the wavelength of 555 nm (yellow).” SRC: https://www.researchgate.net/publication/329747660_Effects_of_the_aging_time_on_CFL_and_LED_lamps_experimental_tests_on_the_electrical_and_photometric_quantities
From my understanding, it’s due to the nature of the light-sensitive cells in your retina. You have three types of cones (and one type of rod), each with a range they are sensitive towards in the visible light spectrum, centered around a particular area thereof. This comes out to favoring yellow and green-yellow.
In additive color, we also create yellow by mixing both red and green, so naturally it’s brighter than both when describing color this way. Similarly magenta > blue or red, and teal > blue or green. Yet of the three, yellow is still ‘brighter’ because of the above.
You know how the visible light spectrum goes “red, orange, yellow, green, blue, indigo, violet”? That’s the chunk of energy that we’re able to see, but there’s more energy “above” and “below” it.
It goes from infrared that we can’t see, to red which is on the edge of what we can see, so it doesn’t look at bright. Then the colors right smack in the middle are easier to see, so they’re brighter-looking. Then as we get closer to ultraviolet that we can’t see, the blues and violets get less bright.
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