Is Black a Colour? Examining the Definition and Perception of Black as a Colour

[thiotimoline]

According to the definition of some online encyclopedias, black is defined as an absence of colour. My own definition of black is a phenomenon which totally absorbs all light shining on it, thus rendering it black. Now, is black considered a colour?

Points raised:

1) In the electromagnetic spectrum, the human eye can ONLY see the visible light part of the spectrum, that is white light consisting of the 7 basic components - red, orange, yellow, green, blue, indigo and violet. This is familiar for those science students. Since black is not one of the 7 basic colours, black itself is not a colour. On the other hand, it can be argued that the random combination of certain, if not all, colours together can produce black. But does that mean that we mix colours together to produce something not considered a colour, something we cannot see? If black is a colour, it should be within the visible light spectrum but apparently it is not.

2) Take a black object and a transparent glass for example. In both cases, light from a source does not reflect back to our eye, but for the black object, light is simply absorbed while the transparent glass actually allows light to pass through. However we compare both cases, since both light does not return to us, by right we should see both as identical but instead we see one as black object, another as a transparent glass. Does the future path of the light determine the 'blackness' of an object?

 

[Danger]

'Colour' is just a term that Anglophones use to describe the various frequencies of electromagnetic radiation. Black is not included. You seem to be using the concepts of 'additive' colour (light) and 'subtractive' colour (pigments) interchangeably, and they're not the same thing.
This has been discussed quite thoroughly before. Please run a forums search to check out the previous threads. If questions remain, we'll look after them for you.

 

[arildno]

Depends on which definition of colour you're using. The scientific definition excludes black, the popular "definition" includes black.

Much the same as the contrasts between the meaning of the poupular terms "energy, work" vs. the scientifically chosen definitions of the same terms.

As long as one is clear about which meaning of the term one is using (popular or scientific), there is no need for further discussion of these topics.

 

[GOD__AM]

If you can see it, it's a color. A black piece of paper certainly is a color. A black hole is not...

 

[russ_watters]

My own definition of black is a phenomenon which totally absorbs all light shining on it, thus rendering it black. Now, is black considered a colour?

No, it is still just the absence of color. If it absorbs all radiation, then it doesn't reflect any to your eyes and your eyes see nothing.

On the other hand, it can be argued that the random combination of certain, if not all, colours together can produce black.

You could argue that, but you'd be wrong. The mixture of all colors is white

Take a black object and a transparent glass for example. In both cases, light from a source does not reflect back to our eye, but for the black object, light is simply absorbed while the transparent glass actually allows light to pass through. However we compare both cases, since both light does not return to us, by right we should see both as identical but instead we see one as black object, another as a transparent glass.

No. We see a glass because some light is reflected.

 

[russ_watters]

If you can see it, it's a color. A black piece of paper certainly is a color.

If it were perfectly black, it would send no light whatsoever into your eye and you would therefore not see it.

 

[GOD__AM]

If it were perfectly black, it would send no light whatsoever into your eye and you would therefore not see it.

Show me any piece of black paper I can't see, with a light shining on it and I'll agree with you...

I would consider some gasses black (like oxygen), but I don't know of any solid objects that can be considered black by your definition. So it's doubtful that a piece of paper can be perfectly black, If I turn my head black paper doesn't send any light into my eye, does that make it perfectly black suddenly?

 

[Danger]

Show me any piece of black paper I can't see, with a light shining on it and I'll agree with you...

I would consider some gasses black (like oxygen), but I don't know of any solid objects that can be considered black by your definition. So it's doubtful that a piece of paper can be perfectly black, If I turn my head black paper doesn't send any light into my eye, does that make it perfectly black suddenly?

That has so be one of the most specious arguements that I've ever seen on behalf of any cause. No paper is perfectly black. You can never see perfect black. Even if such were right before your eyes, and you had your eyes shut, random photonic events or brain aberations would give specks of light.
Oxygen, or any other gas, is colourless, not black. Would you describe steam from a teakettle as 'black'?

 

[Chronos]

A thought experiment: A piece of cardboard in a room [let's say the room is painted flat white just for the sake of argument] lit by a single candle placed in the line of sight between myself and the candle flame. Can I 'see' something is there? I would unequivocally say 'yes', would characterize its 'color' as black, and deem it compelling evidence that 'black' is the absence of light.

An old friend of mine, who was losing his sight due to glaucoma, explained it best:

"Only two colors exist for me now - black and not-black."

 

[GOD__AM]

That has so be one of the most specious arguements that I've ever seen on behalf of any cause. No paper is perfectly black. You can never see perfect black. Even if such were right before your eyes, and you had your eyes shut, random photonic events or brain aberations would give specks of light.
Oxygen, or any other gas, is colourless, not black. Would you describe steam from a teakettle as 'black'?

In the scientific definition of black you are right, but we as everyday people call things by the color black (a car for instance). Now scientifically you would argue with me that what I call a black car is not black, and you would be right, but I'll continue to refer to it's color as black.

If something emits or reflects no electromagnetic radiation in the visible spectrum, it is black by definition. Oxygen therefore is black. Colorless and black are the same thing by scientific definition.

Steam reflects light back to me so no I wouldn't call it black or colorless.

I know I am presenting two different views here, but I think they both have a proper context.

 

[Danger]

I see your point, but still disagree with it from the scientific viewpoint (and this is a science site, after all).
To start with, the aforementioned black cardboard is absorbtive of visible EM, but most likely reflects in other wavelengths. For the sake of arguement, I'm accepting that. If you try looking at paint chips or a Pantone chart, though, you'll see that there are an awful lot of different colours deemed 'black'. Obviously, their reflective/absorbtive qualities are different.
As to my reference to steam, I meant the actual steam rather than the condensed water that you can see. It's invisible. If you take that to mean black, as you suggested, then you could call space black... and it doesn't even exist. How can 'nothing' have a colour quality?
Chronos, in your example you are not 'seeing' the object. You're seeing the shadow of the object. It could be any colour, and you wouldn't be able to tell (as long as the ambient light is strong enough). All you can know is that there is something blocking the light.

 

[russ_watters]

That has so be one of the most specious arguements that I've ever seen on behalf of any cause.

Jeez, I'm glad you said it before me. Now I don't need to go bang my head against a wall. :grumpy:

 

[russ_watters]

In the scientific definition of black you are right, but we as everyday people call things by the color black (a car for instance). Now scientifically you would argue with me that what I call a black car is not black, and you would be right, but I'll continue to refer to it's color as black.

You can, of course, believe whatever you want, but this is a science site and from a scientific point of view, the question has an unequivocable right and wrong answer. You are not helping by providing the wrong answer.

 

[Gokul43201]

If something emits or reflects no electromagnetic radiation in the visible spectrum, it is black by definition.

Where did you find this "definition"?

 

[arildno]

I would like to say that if we look at our actual PERCEPTION of colours, rather than the physical basis of colours (which is "common man's" way of defining colours), then "blackness" is not perceived as something essentially different than colours proper.

There is not anything inherently wrong with using actual perceptions as a naive classification scheme for "colours", but it is a scientifically useless definition.

Other than charting our perceptions, that is..

 

[GOD__AM]

Where did you find this "definition"?

It's not a definition, I'm simply relating conditions of matter that fit it into the definition of black. If you have something else to offer I'm all ears.

If someone here doesn't agree that by definition oxygen, and other colorless gases fit into the definition of black, then I would like an example of something that is black, other than a black hole, which I hope we all agree on.

 

[thiotimoline]

Ok I agree with you that for glass, some light is reflected thus we can see the glass. But if we follow the definition that black is absence of colour, then that means no light can reflect back to our eye and we will see nothing, but how come we still can see that 'black' object? Also. If black is a colour, what is its wavelength? If you say it is a colour we can see, then it must have a wavelength between 400nm and 700nm so that it can be part of the visible light of the EM spectrum right?

 

[Chaos' lil bro Order]

Now you guys are arguing two different points, one is talking about color pigments, the other is talking about colored light. Heck their additive theories are completely different, pigments use R Y B for primaries, and light uses R G B for primaries. By definition you are both correct, but there are two definitions. Pigment black is the addition of all the colors together, while light black is simply the the existence of no light at all, or of Electromagnetic light outside of our visible range. As in Infrared light just below our visible red and Ultraviolet just above our visible purple.

So I'm guessing you are both right, just taking different perspectives since the original question was a little confusing.

 

[Gokul43201]

It's not a definition, I'm simply relating conditions of matter that fit it into the definition of black.

And I'm asking you how you came up with that definition of black?

If you have something else to offer I'm all ears.

A thing is black if it absorbs all the visible radiation incident upon it.

If someone here doesn't agree that by definition oxygen, and other colorless gases fit into the definition of black, then I would like an example of something that is black, other than a black hole, which I hope we all agree on.

Why? I can perfectly well define 0 Kelvin, but you won't accept the definition unless I can give you an example of something at 0 Kelvin?

 

[GOD__AM]

And I'm asking you how you came up with that definition of black?

A thing is black if it absorbs all the visible radiation incident upon it.

Why? I can perfectly well define 0 Kelvin, but you won't accept the definition unless I can give you an example of something at 0 Kelvin?

Why do you keep asking the same question, I already answered it. You want to talk about 0 kelvin, fine. Something that absorbs all visible light obviously doesn't reflect any... Something at 0 kelvin obviously doesn't emit any light... Do you still need to know where I got the definition of black to qualify the above statements? It's irrelivant to the discussion, and just seems more like badgering.

The issue of wether 0 kelvin exists has been done in many other threads, why start all that again?

All I'm asking for is a real world example of something black. If you don't know of any fine, just say I don't know.

 

[DaveC426913]

...I would like an example of something that is black, other than a black hole, which I hope we all agree on.

The ceiling of my room with the lights off.

No light falls upon my eye. It is not a black hole.

Note, by the way, this fails the condition of "absorbing all light incident upon it", showing that that is an invalid condition.

Technically, the only necessary condition of black is "no light is emitted from it."

 

[DaveC426913]

This entire discussion revolves around the context of the working definition of colour.

There are colours:
- that our eyes are receptive to
- the Newton defined in a rainbow
- that pigments produce
- that light produces
and more.

These are all separate definitions of colour and they are all valid.
The moment you pick one, almost all the above dischord will disappear.

 

[GOD__AM]

The ceiling of my room with the lights off.

No light falls upon my eye. It is not a black hole.

Note, by the way, this fails the condition of "absorbing all light incident upon it", showing that that is an invalid condition.

Technically, the only necessary condition of black is "no light is emitted from it."

This argument falls into line with the comment I made about turning my head away from the paper. It was dismissed quickly, and rightfully so. If an object is truly black you can't see it even when the lights are on...

 

[DaveC426913]

If an object is truly black...

There is no such thing as an object that is "truly" any colour.

The colour of an object is detemined by the light that impinges on it, and only influenced by the properties of the object itself.

If I have an object that reflects yellow light and
- we shine a yellow light on it, it will appear bright yellow.
- we shine a green light on it, it will appear dark green.
- we shine a blue light on it, no colour will be perceptible. (i.e. black - it is not yellow or anything else)

The point here being that an object cannot reflect any colour that it is not "given" in the first place.

 

[Mk]

This discussion is silly.

If something emits or reflects no electromagnetic radiation in the visible spectrum, it is black by definition.

I don't know about you but I think oxygen would be transparent—not black.

The differences between (perfect), white, mirrors, black, and transparent are as follow (correct me if I'm wrong):

Perfect white means that when white light is on it, all colors are reflected equally. A mirror would reflect all colors period, no equality. Blackness means all visible light is absorbed, and none reemitted. Transparent means light goes straight through.

 

[GOD__AM]

This discussion is silly.

I don't know about you but I think oxygen would be transparent—not black.

The differences between (perfect), white, mirrors, black, and transparent are as follow (correct me if I'm wrong):

Perfect white means that when white light is on it, all colors are reflected equally. A mirror would reflect all colors period, no equality. Blackness means all visible light is absorbed, and none reemitted. Transparent means light goes straight through.

What happens to light when it hits an oxygen atom? Does it just go right through as if the oxygen atom isn't even there, with no interaction at all?

Is there no chance that the light is absorbed by the atom, then is emmited as a wavelength outside the visible spectrum?

If the second question is true then oxygen is black.

If the first one is true, then please explain how it is impossible for light to not interact with oxygen in any way. I believe the speed of light is slowed somewhat when moving through oxygen (maybe I'm mistaken) and if it is, there is some interaction taking place. Interaction would have to be absorbing visible light, but not emiting any ie; black.

 

[Chaos' lil bro Order]

Technically, the only necessary condition of black is "no light is emitted from it."

Dave gives the best answer so far. This definition satisfies that an object can be black because any incident light is absorbed by it and that an object can be black because there is no incident light whatsoever. The point is, as Dave succinctly pointed out, is that 'no light is emitted from [the object].'

All other discussion is wrong.

 

[Mace]

Hi could be

Black can't be made by waves of eletricity (like all the other colors), however, there are black objects in the world, such as black paper, black "stuff". In art white & black are not a colors (becuase they can't be made with any primary colors {blue,yellow,red}). However, there is such thing as white light...

So why can't there be anything such as black light? well if white light needs all (+) power turned on, then black being the opsite, has to have (-) power turning it on, which is not possable {today "(-) power" is just basically no power, with no current at all, with no current no power, with no power no light}. However, this can be inproved, if today's power had (+) current and (-) current, when maybe you can make black light.

Why have light dicide the colors in the world? well without light u can't see any colors, why? all the colors you see are made from white light, everything. The white light mixes with the "color thing" to make the colors we see. (they act like capacitors, for light {increseing or decresing the amount of vabriation} making different colors).

 

[DaveC426913]

In art white & black are not a colors (becuase they can't be made with any primary colors {blue,yellow,red}).

I refute that there is any such definition in the art world.


The closest you'll come is that black and white have no hue - they do not change the colour of other colours, they only change the value.


The rest of that post is pretty much nonsense.

 

[DaveC426913]

Dave gives the best answer so far... The point is, as Dave succinctly pointed out, is that 'no light is emitted from [the object].' All other discussion is wrong.

*bask*

 

[Andrew Mason]

What happens to light when it hits an oxygen atom? Does it just go right through as if the oxygen atom isn't even there, with no interaction at all?

Is there no chance that the light is absorbed by the atom, then is emmited as a wavelength outside the visible spectrum?

If the second question is true then oxygen is black.

If the first one is true, then please explain how it is impossible for light to not interact with oxygen in any way. I believe the speed of light is slowed somewhat when moving through oxygen (maybe I'm mistaken) and if it is, there is some interaction taking place. Interaction would have to be absorbing visible light, but not emiting any ie; black.

This is one of the few interesting points in this rather mixed up thread.

The colour of an object has to do with how white light interacts with the object. Colour of an object denotes a quality of the object's ability to absorb parts of white light and reflect others. I would suggest that colour' is something that only significant clusters of molecules possess, not individual atoms.

[A single atom, such as hydrogen, can have a characteristic spectrum due to its electron configuration. But this is not its colour. ]

AM

 

[Danger]

Dave gives the best answer so far. All other discussion is wrong.

At the risk of my immortal ego, I must agree. Now if he could just figure out how to build a decent swimming pool... :tongue:

 

[GOD__AM]

Quote:
Originally Posted by DaveC426913
Technically, the only necessary condition of black is "no light is emitted from it."

Dave gives the best answer so far. This definition satisfies that an object can be black because any incident light is absorbed by it and that an object can be black because there is no incident light whatsoever. The point is, as Dave succinctly pointed out, is that 'no light is emitted from [the object].'

All other discussion is wrong.

If something emits or reflects no electromagnetic radiation in the visible spectrum, it is black by definition.

 

[Danger]

Is it just me, or has this dead horse been beaten to the point that it can't be resurrected?

 

[Mk]

I'm sure it'll happen before tomorrow.