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Re >> "with an ability to reflect around 98% of incoming sunlight" Seems like a mirror would reflect even more light. Now, obviously we don't want to make the exteriors of our buildings and cars a mirror! . but it made me wonder: What's the difference between a really really really white paint that reflects 98%+ light, vs. a reflective surface? Is it that the white paint reflects the light, but in a "scrambled" form,…
I found this video about the topic to be interesting: https://www.youtube.com/watch?v=1n_otIs6z6E (title: Why aren't Mirrors White? Why isn't EVERYTHING a Mirror?)
Re >> "with an ability to reflect around 98% of incoming sunlight" Seems like a mirror would reflect even more light. Now, obviously we don't want to make the exteriors of our buildings and cars a mirror! . but it made me wonder: What's the difference between a really really really white paint that reflects 98%+ light, vs. a reflective surface? Is it that the white paint reflects the light, but in a "scrambled" form,…
Silver reflectivity is about 95%, aluminum reflectivity is about 90%.
So the best metallic mirrors are worse than the best white paints, even if they can be better than the frequently used white paints based on titanium white (89.5% reflectivity).
Total internal reflection might be closer to 100%, but that cannot be used for the light that comes from the air on the surface of a mirror.
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Back into space. Seems fine.
edit: This doesn't mean that the paint isn't effective for what the researchers want it to do, in case that wasn't clear
Re >> "with an ability to reflect around 98% of incoming sunlight" Seems like a mirror would reflect even more light. Now, obviously we don't want to make the exteriors of our buildings and cars a mirror! . but it made me wonder: What's the difference between a really really really white paint that reflects 98%+ light, vs. a reflective surface? Is it that the white paint reflects the light, but in a "scrambled" form,…
Nope. Silver reflectivity is about 95%, aluminum reflectivity is about 90%. So the best metallic mirrors are worse than the best white paints, even if they can be better than the frequently used white paints based on titanium white (89.5% reflectivity). Total internal reflection might be closer to 100%, but that cannot be used for the light that comes from the air on the surface of a mirror.
edit: here's an example: https://i.imgur.com/Ar80FYZ.jpeg
> The new material features boron nitride in hexagonal nanoplatelet form and offers a solar reflectance of 97.9% What's the difference between white paint and a mirror? Scatter?
> The new material features boron nitride in hexagonal nanoplatelet form and offers a solar reflectance of 97.9% What's the difference between white paint and a mirror? Scatter?
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Nope. Silver reflectivity is about 95%, aluminum reflectivity is about 90%. So the best metallic mirrors are worse than the best white paints, even if they can be better than the frequently used white paints based on titanium white (89.5% reflectivity). Total internal reflection might be closer to 100%, but that cannot be used for the light that comes from the air on the surface of a mirror.
A simple way to verify this is to observe that common mirrors also tend to be green, showing that the other colors are absorbed more by the mirror. If you face two mirrors towards each other you will see a lot of green. edit: here's an example: https://i.imgur.com/Ar80FYZ.jpeg
The better mirrors, which are used e.g. in telescopes and some other optical instruments, have the metal on the front side, but that limits the metal choice to aluminum, because silver is tarnished quickly by the sulfur compounds present in the air.
How does this new paint compare to the contents of a spray paint can from Home Depot? Having a hard time searching the web for this one, the first few pages of hits are all about this new 98.1% paint.
You can get 90-94% in wall paints; not sure about spray paints.
https://www.kylieminteriors.ca/paint-colour-review-the-5-whi...
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Yes, it's not reflecting the light so much as re-radiating it in a diffuse pattern.
I don’t think there’s a physical difference between reflection and re-radiation, is there? Reflection is just highly organized/non-diffuse.
