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, thus losing the image?
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 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.
I do not know when aluminum has replaced silver, but it was probably not a long time after WW2.
The silver mirrors had the advantage that the metal could be easily deposited from a water solution, anyone could make silver mirrors at home, if desired.
The aluminum mirrors use a vacuum deposition process, which requires very expensive equipment, but the cost per mirror is much less.
https://materion.com/products/precision-optics/application-f...
Most dielectric coatings absorb ultraviolet light so they reflect much less of the total solar light, most likely less than 90%.
Such a mirror with dielectric coatings would not be able to cool the object on which it is applied, unlike the paints which are discussed in the article, which are based on boron nitride, barium sulfate, calcium carbonate or fluorinated polymers, all of which do not absorb ultraviolet light.
The common white paints based on titanium white or zinc white also absorb ultraviolet light, so they cannot be used for cooling an object illuminated by the Sun.
https://www.researchgate.net/figure/Reflectance-versus-wavel...
https://www.researchgate.net/figure/Reflectance-of-Ag-Au-and...
I think this better fits my observation that a clean mirror can easily be unnoticed in an environment similar in all directions, such as woodland or a messy room.
Aluminum has lower reflectivity everywhere, but it retains a high reflectivity in ultraviolet.
Silver absorbs ultraviolet, which lowers the integrated reflectivity over the complete spectrum.
A few percent difference in the total reflectivity can make a large difference in the cooling power of a paint, but a few percent difference in the reflectivity of a mirror is unlikely to be perceived visually.
Maybe quantum physicists will disagree but the difference between a mirror and a white surface is that a mirror is perfectly flat and therefore will reflect light at always the same angle. It may absorb some of it, or even most of it (black mirror!) but what it reflects, it will do it always the same way.
A white painted surface can be thought as a surface covered in tiny mirrors, all pointed in a different direction, and depending on which tiny mirror a ray of light will hit, it will be reflected in a different direction. With large pieces, like with a broken mirror, you will still see (as you said) scrambled images. But because the pieces are so tiny, you won't be able to make out an image and you will only see white. A glass pane can look like a mirror, but reduce it to a powder and it becomes white. It has nothing to do with absorption, you can have a 1% reflective mirror, and 100% reflective diffuse white.
The way the "tiny mirrors" that make up the white paint are oriented give out its general look. Have them oriented mostly with the surface and you get a glossy finish, have them randomly oriented in many directions and you get a matte finish (this is called specular reflection btw).
I've seen mirrors be called "smart white", it is white because it reflects most light in most wavelengths, and it is smart because it keeps the rays of light oriented.
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?)