What Colour Is A Mirror?
A question most people don’t really think to ask but nonetheless are super fascinated by: What colour is a mirror?
When you stop to consider ‘what is the colour of a mirror?’, the first thing you might think is that they’re silver. This is, after all, how we’ve seen mirrors represented in the cartoons of our childhood.
This, however is incorrect.
A mirror often appears silver to the human eye because the reflective layer contains metal. However, a mirror is not silver or grey. Not at all.
- Related: Check out this hilarious pics of people trying to sell mirrors and accidentally catching all the wrong things!
How We See Colour
Here’s where things get super fascinating. Humans perceive colour through the electromagnetic spectrum, which makes up a range of wavelengths that are visible and invisible to the human eye.
The visible portion of the spectrum spans wavelengths from around 400 nm to 700 nm. Because of this, colours like indigo, blue, green, orange, yellow, and red map to the spectrum in order of increasing wavelength.
When light comes into contact with an object, the object absorbs specific wavelengths from a visible spectrum. The visible-spectrum wavelengths which are not absorbed are reflected. Reflected wavelengths that find their way to your eyes can be perceived as any number of colours.
Objects that absorb all visible wavelengths are seen as black, however, this that reflect the visible wavelengths are seen as white.
Are Mirrors Silver Or Clear?
Now that we know a mirror is not silver… is it clear?
The truth to this is that a typical mirror actually tends to be more of a green tint than any other colour. They only appear silver because they include a highly reflective metal, which makes them have a silver or ‘clear’ look.
A mirror will generally reflect more for the green wavelength of colour than red or blue light. How the light interacts with the atomic structure of the mirror is crucial to this equation. In fact, it largely impacts the images we see when looking in the mirror.
How Reflections Work
Mirrors, similar to things that appear white to our eyes, reflect all visible wavelengths.
In this case, there are different ways to reflect light. Mirrors have what’s called a “specular reflection”. This means that the wavelengths that leave a mirror’s surface are organized to the angle and configuration of the mirror itself.
In other words, a mirror builds an image of the source of the light.
- Related: Have you heard of the Troxler Effect? Check out this post on how looking in a mirror can be downright creepy.
Most mirrors are composed of a soda-lime silica glass substrate with a silver backing, as we’ve discussed. The substrate backing is the optical core of most common mirrors, and what gives it the reflective quality.
Second Surface Vs First Surface Mirrors
There are two main types of mirrors: second-surface mirrors and first-surface mirrors.
A second-surface mirror has a layer of glass in the front of the silver backing reflective part. The silver part of it does not mean the metal used is actual silver. Other metals, for example aluminium, zinc, gold, or copper, may be used. The second-surface mirror is made for use in homes.
A first-surface mirror has its reflective layer at the front of the mirror instead of the back. This makes it about 10% more reflective than a second-surface mirror. First-surface mirrors are manufactured for optical equipment like cameras, microscopes, and telescopes. They’re designed for minimal image distortion and more scientific applications.
How An Imperfect Mirror Affects What You See
If there are any glitches, dents, or general imperfections in a mirror, it will naturally distort the image you see.
You’ll perhaps have noticed this when trying on clothes in a store. Some of the mirrors make you look like a bit of a model, while others make you look like a bit of a walrus.
Mirrors can be distorted in ways that will manipulate their reflections intentionally (say, perhaps, a bathing suit change room that wants to sell you expensive bikinis) or sometimes when they’re mass produced, they’re just naturally distorted from careless manufacturing.
Either way, imperfect mirrors will not only reflect the subject that’s being seen in them, but also the spectrum of light that’s reflected on them.
Okay So In Simple Terms, What Colour Are Mirrors?
In simple terms, a mirror is whatever colour it’s reflecting at any given time. However, real mirrors aren’t perfect. Their surface atoms give any reflection a very slight green tinge as the atoms in the glass reflect whatever is in front of it.
So more than white or silver, a mirror reflects back green light more than any other colour.
In the simplest terms, if you have to nail down the colour of a mirror, it’s actually green.