Black is said to absorb all colors of light, so why can a black surface be reflective, such as a black painted car.
In: Physics
Light can bounce off of surfaces like a ball. When it hits the surface in an angle from the left, it bounces with the same angle to the right. If all light bounces like this, you can see a reflection. This is how mirrors bounce light.
Light can also scatter all around to all directions. A very white surface may bounce almost all the light but you won’t see a reflection because the light bounces to all directions and the “reflection” becomes blurry.
Now, a perfectly black material wouldn’t bounce any light at all but it it impossible to make a perfectly black surface. Surfaces can be very dark but not black. If the black sufrace bounces the small amount of light like a mirror, it looks shiny.
The glossy surface can be from polished clear coating applied on top of the paint.
When light hits the surface, some amount first bounces off that coating layer and you see a glossy, mirror-like reflection. The remaining light transmits through the coating onto the black paint and most of it gets absorbed.
You can do the same by polishing the paint to a mirror finish. Then, some portion of light is reflected like a mirror rather than scattered back like if you shined light on a piece of paper.
stuff we see everyday isn’t very good at blocking everything, but still good enough that we see colors
In a glossy black surface surface the part of light that doesn’t get absorbed is reflected without being scattered all around, making the surface look glossy, but it’s still a lot less than if it were a mirror
This was addressed in a recent explanation either here or on /r/askscience. I’m still trying to find it. In the mean time, I’ll give a summary.
Objects reflect light in two ways. One is called specular reflection, in which a ray of light bounces off the object and leaves in a new direction, still a single ray of light. Objects that reflect light in this way appear shiny or glossy. The other is called diffuse reflection, in which the ray of light hits the object and is scattered in all directions. This kind of reflection is what gives objects their color.
An object with low diffuse reflection will appear black, but it can still have good specular reflection, making it appear glossy. Really wish I could explain better. I’ll keep looking for the comment.
No object on earth is truly black it will always reflect some light back. If it’s a Matt finish then all that is happening is that the reflected light is scattering in all directions so not much of it reaches your eyes, if it’s a glossy surface then the reflected light is going in roughly the same direction so you can see the image that is being reflected. The colour and the luminosity will be greatly reduced as it’s mostly being absorbed hence why black objects get hotter in sunlight than white objects.
For one, a painted black car has a shiny coating on the outside which will make the sun reflect on it. Most blacks are not true black. True black is not a color because true black will not reflect any light. If you look up videos of the color vantablack, you can see how much light is absorbed by it (keep in mind vantablack is still a color/not true black, but it does absorb much more light than other blacks
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