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

[thiotimoline]

So do we have a answer as to whether black is a colour or not?

 

[rcgldr]

So do we have a answer as to whether black is a color or not?

Wiki includes "black" in its list of colors (what could be more convincing?):

list of colors page

Also on my computer, if I right click the mouse to setup a "desktop" color, and select R,G,B = 0,0,0, I don't get a pop-up dialog box warning me that black isn't a color.

Since the absence (or near absence) of light can be perceived (a person knows when something is dark or black), then in that sense, black is a color.

 

[Andrew Mason]

Wiki includes "black" in its list of colors (what could be more convincing?):

list of colors page

Also on my computer, if I right click the mouse to setup a "desktop" color, and select R,G,B = 0,0,0, I don't get a pop-up dialog box warning me that black isn't a color.

Since the absence (or near absence) of light can be perceived (a person knows when something is dark or black), then in that sense, black is a color.

So we can all agree that black is a colour if you define colour a certain way and is not a colour if we define it another way.

If we define colour as a quality of the light or absence of light that emanates from an object as perceived by our eyes and brains (including white and black provided you are not totally colour blind, in which case neither black nor white would be a colour), black is a colour. If we define it as a frequency of light, black is not a colour. If we define colour as a flavour of quarks ...

So the conclusion is obvious. Non-colour blind human beings believe black is a colour. Physicists believe it is not.

Therefore physicists are all colour blind or non-human.

AM

 

[rcgldr]

Therefore physicists are all colour blind or non-human.

That explains why they dress the way they do.

 

[-Job-]

Let me list the two definitions here, then:
- color as an abstract human concept -> black is a color
- color as a certain frequency of light -> black isn't a color

Maybe now we can move on to something more worthwhile.

 

[Danger]

Right... so on to the important one. Is orange a colour or a flavour?

 

[Gokul43201]

Why do you keep asking the same question, I already answered it.

No, you have not. If you think you have, you have either not read carefully what you've written, or you don't know what a definition is.

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?

You've completely failed to see the logic in the argument. I just provided you with a violation of the requirement you've imposed that a "real world" example is required, for a definition to be meaningful.

All I'm asking for is a real world example of something black.

To what end? Just plucked a hair from my head - it's black.

 

[Gokul43201]

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.

Ouch! Can't disagree more. Is a perfect reflector black?

 

[NoTime]

In general you only see three colors.
Red, Green and Blue.
It's the stucture of the eye.

Any other color you think you see is all in your head. :zzz:

Ouch! Can't disagree more. Is a perfect reflector black?

You getting picky about emission vs reflection?

 

[Chaos' lil bro Order]

Now why oh why is the sky blue?

 

[rcgldr]

In general you only see three colors. Red, Green and Blue.

Actually green, yellowish green (these two very close together), and bluish violet.

Spectral colors can be observed from a single frequency source, or from a multi-frequency source. Non-spectral colors (for example, grey) require multiple frequencies.

http://en.wikipedia.org/wiki/Color#Spectral_colors

Any other color you think you see is all in your head.

True.

 

[thiotimoline]

Wiki includes "black" in its list of colors (what could be more convincing?):

list of colors page

Also on my computer, if I right click the mouse to setup a "desktop" color, and select R,G,B = 0,0,0, I don't get a pop-up dialog box warning me that black isn't a color.

Since the absence (or near absence) of light can be perceived (a person knows when something is dark or black), then in that sense, black is a color.

But the problem is, if no light comes back to us, how can we say that black is a colour?

 

[zoobyshoe]

But the problem is, if no light comes back to us, how can we say that black is a colour?

The notion of black as a color preceeded the scientific understanding of the cause of the phenomenon of color by tens of thousands of years. It arises from the nomenclature for pigments. Primitive man, for instance, smeared himself with soot and charcoal in preparation for rituals and the color of it had specific meaning. The color had to be named to distinguish it from the white china clay he might use on a different occasion or the yellow ochre he might use on another.

We can call black a color because it's part and parcel of the in-place nomenclature for pigments.

A lady goes into a fabric store and hands the clerk a list of "colors" she needs: red, orange, black. She's making a halloween costume. Black is tacitly accepted as a proper color, no one gets upset, no one has been harmed.

Although it's nice to understand that the phenomenon of black results from the absense of the EM waves that cause the other colors, the notion of banging your head against the wall wondering if it's still proper to refer to it as a color is an obvious waste of time.

 

[ZapperZ]

The notion of black as a color preceeded the scientific understanding of the cause of the phenomenon of color by tens of thousands of years. It arises from the nomenclature for pigments. Primitive man, for instance, smeared himself with soot and charcoal in preparation for rituals and the color of it had specific meaning. The color had to be named to distinguish it from the white china clay he might use on a different occasion or the yellow ochre he might use on another.

We can call black a color because it's part and parcel of the in-place nomenclature for pigments.

A lady goes into a fabric store and hands the clerk a list of "colors" she needs: red, orange, black. She's making a halloween costume. Black is tacitly accepted as a proper color, no one gets upset, no one has been harmed.

Although it's nice to understand that the phenomenon of black results from the absense of the EM waves that cause the other colors, the notion of banging your head against the wall wondering if it's still proper to refer to it as a color is an obvious waste of time.

Very well said. In addition, I would like to offer this analogous situation.

Would one consider the absence of matter to be the same as the matter itself? For example, would a water bubble (the absence of water in a particular volume) be considered the same thing as a drop of water (a volume of water in an environment that is absent of water)? In physics (this is, after all, in the physics forum), both are treated in the same manner and on equal footing.

The clearest example of this is the "holes" that are present inside metals, semiconductors, and insulators. Even though this is nothing more than an absent of electrons, they are treated the same way as if it is a well-defined particles like an electron. It has a charge (positive), a mass, a "spin", etc...etc. Yet, it is nothing more than a vacancy. If the holes are the majority charge carrier in a semiconductor, we call that a p-type semiconductor.

So you can accept "black" as being a color based on cultural practices, AND, the fact that there's precedent in physics for accepting the absence of something to be the same as the "thing" itself.

Hopefully, this thread will reach its resting conclusion soon.

Zz.

 

[DaveC426913]

Just plucked a hair from my head - it's black.

It is? Are you of Asian descent? Most black hair is - upon close examination - dark brown.*runs and hides*

 

[Farsight]

I reckon black is an absence of colour, so it's not really a colour. But it is on my colour chart, and I am wearing black jeans. So if somebody wants to say black is a colour fair enough. Or color. I'm easy.
The thing is, none of these "colours" really exist anyhow. I mean, I might ask "Is red is a colour?", and everybody would say yes. But colour is just something in our heads, the brain's shorthand "colour coding" for frequency. Colour doesn't really exist. It really doesn't. We only think it exists.

But it doesn't really!

 

[zoobyshoe]

But colour is just something in our heads, the brain's shorthand "colour coding" for frequency. Colour doesn't really exist. It really doesn't. We only think it exists.

But it doesn't really!

The brain sorts out the frequencies, dresses them up, so to speak, and presents them to consciousness as the colors we know and love.

 

[GeoMike]

The brain sorts out the frequencies, dresses them up, so to speak, and presents them to consciousness as the colors we know and love.

Makes your brain hurt trying to imagine what new "colors" infrared and ultraviolet would be if we could "see" them.

-GeoMike-

 

[zoobyshoe]

Makes your brain hurt trying to imagine what new "colors" infrared and ultraviolet would be if we could "see" them.

That would be so cool to have two new colors!

 

[ZapperZ]

I reckon black is an absence of colour, so it's not really a colour. But it is on my colour chart, and I am wearing black jeans. So if somebody wants to say black is a colour fair enough. Or color. I'm easy.
The thing is, none of these "colours" really exist anyhow. I mean, I might ask "Is red is a colour?", and everybody would say yes. But colour is just something in our heads, the brain's shorthand "colour coding" for frequency. Colour doesn't really exist. It really doesn't. We only think it exists.

But it doesn't really!

Then you don't exist either. Would you rather this thread be moved to the philosophy forum where this type of discussion can go on ad nauseum?

Zz.

 

[zoobyshoe]

Then you don't exist either. Would you rather this thread be moved to the philosophy forum where this type of discussion can go on ad nauseum?

Zz.

Actually ZapperZ, his post is factual and not philosophical. Colors as we experience them are created in the brain and are not a property of the EM wavelengths they represent. There is no objective reason that EM wavelengths between 625 and 740 nanometers should look red to us. There's no reason any color should be anything but a shade of grey. Our brains add the spice of colors as we percieve them. This is a neurological fact that you could confirm with Mentor Hypnagogue or selfAdjoint.

 

[redrocks]

hmmmm... in the art world Black is a Shade.

 

[zoobyshoe]

hmmmm... in the art world Black is a Shade.

But so is white, and every level of grey in between.

 

[Gokul43201]

Actually ZapperZ, his post is factual and not philosophical. Colors as we experience them are created in the brain and are not a property of the EM wavelengths they represent. There is no objective reason that EM wavelengths between 625 and 740 nanometers should look red to us. There's no reason any color should be anything but a shade of grey. Our brains add the spice of colors as we percieve them. This is a neurological fact that you could confirm with Mentor Hypnagogue or selfAdjoint.

Is the frequency of a radiation any more a real property of the radiation than its "color" is?

The frequency is simply a number that is spit out by a machine (a spectrometer) that is irradiated by the light. The color is, in much the same way, a signal spit out by a different kind of machine (an eye), when exposed to the same light.

This does become a philosophical discussion.

 

[zoobyshoe]

Is the frequency of a radiation any more a real property of the radiation than its "color" is?

The frequency is simply a number that is spit out by a machine (a spectrometer) that is irradiated by the light.

This, I don't understand, so you'll have to explain it. I started a thread once asking what was meant by the term "frequency" when applied to photons, but it didn't seem anyone could put it in terms accessible to someone who hadn't studied quantum physics. I did leave, however, with the distinct impression that photons are authentically doing something at the specific frequencies ascribed to them; changing their quantum phase or some such. No one suggested anything to the effect that the frequencies might be fictional or arbitrarily ascribed.

The color is, in much the same way, a signal spit out by a different kind of machine (an eye), when exposed to the same light.

The eye is a reciever and the signals it gathers are sent to various parts of the brain for processing. At the end it of it all, different ranges of frequencies are presented to consciousness as red, blue, yellow, and so forth. So, the cones gather the frequencies selectively but the "machine" responsible for fictitiously enriching them into the experience of color, is the brain.

We have to suppose this was the same kind of accidental mutation that goes on all the time in evolution. Despite being a "fictional" perception it proved so much more useful in sorting the environment out than just seeing things in many shades of grey, that the first people who saw this way did better than their black and white visioned contemporaries and eventually supplanted them.

 

[ZapperZ]

Actually ZapperZ, his post is factual and not philosophical. Colors as we experience them are created in the brain and are not a property of the EM wavelengths they represent. There is no objective reason that EM wavelengths between 625 and 740 nanometers should look red to us. There's no reason any color should be anything but a shade of grey. Our brains add the spice of colors as we percieve them. This is a neurological fact that you could confirm with Mentor Hypnagogue or selfAdjoint.

It does become "philosophical" when you start to consider if something "exist". "color" is how we perceive certain EM frequency. It isn't quantitatively accurate, but it is certainly not something we imagined. It is no different than having a trigger that goes BAM when an EM radiation of a certain frequency hits it.

If you accept his logic as color not existing, then you should accept also that you don't exist, because all you are is what *I* perceived in my brain. This is what I mean as it being no longer a physics discussion.

Zz.

 

[zoobyshoe]

It does become "philosophical" when you start to consider if something "exist". "color" is how we perceive certain EM frequency. It isn't quantitatively accurate, but it is certainly not something we imagined. It is no different than having a trigger that goes BAM when an EM radiation of a certain frequency hits it.

If you accept his logic as color not existing, then you should accept also that you don't exist, because all you are is what *I* perceived in my brain. This is what I mean as it being no longer a physics discussion.

Zz.

I think I understand your objection to what he said.

When I read it, I disliked the way he said it, but didn't take it to be the grounds of anything like a developed philosophical stance, just a poorly expressed, over exited reaction to an "amazing" piece of information. My mind was boggled when I first found this out as well, so I refrained from pointing out that saying "We only think it exists" is not an articulate way of expressing the phenomenon of our experience of color. I thought he just lacked the sophistication to phrase it in a way that wasn't inadvertantly misleading.

 

[Danger]

We have to suppose this was the same kind of accidental mutation that goes on all the time in evolution. Despite being a "fictional" perception it proved so much more useful in sorting the environment out than just seeing things in many shades of grey, that the first people who saw this way did better than their black and white visioned contemporaries and eventually supplanted them.

I can't remember the details, but a SciAm article a couple of issues back on how birds see provides evidence that early humans (or their forebearers) possessed 4 types of cone cells and degraded to the 3 that we now have.

 

[zoobyshoe]

I can't remember the details, but a SciAm article a couple of issues back on how birds see provides evidence that early humans (or their forebearers) possessed 4 types of cone cells and degraded to the 3 that we now have.

I read that, at least some birds, can see in the ultraviolet range. So it sounds like the article you read is suggesting humans once could as well.

You recall what made them suspect this?

 

[Danger]

Not right off, but I still have the issue at home. I think that it was by tracking eye development through various stages of evolution in general to see where birds and mammals differentiated as to visual structures. I'll look for it when I'm done work.

 

[NoTime]

I can't remember the details, but a SciAm article a couple of issues back on how birds see provides evidence that early humans (or their forebearers) possessed 4 types of cone cells and degraded to the 3 that we now have.

Actualy, some still do, but IIRC its lower into the red not UV.

A small mention of tetrachromats in the following
http://en.wikipedia.org/wiki/Color#Spectral_colors

 

[zoobyshoe]

Actualy, some still do, but IIRC its lower into the red not UV.

A small mention of tetrachromats in the following
http://en.wikipedia.org/wiki/Color#Spectral_colors

But not infra-red, (which would be cool):

Also, evidence suggests that some very few humans are tetrachromats, a phenomenon which presumably arises when an individual receives two slightly different copies of the gene for either the medium- or long-wave cones. It can be supposed that, for genetic reasons, the small numbers of human tetrachromats that do exist are overwhelmingly female. Their color discriminations are only slightly enhanced, but their brains do appear to adapt to use the additional color information.

 

[Chaos' lil bro Order]

Originally Posted by Chaos' lil bro Order
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.

Ouch! Can't disagree more. Is a perfect reflector black?

I'm not sure I understand your objection Gokul. I don't recall saying perfect reflection makes an object black. Can you elaborate please.

 

[Chaos' lil bro Order]

Bees can see the UV rays emitted from flowering plants (read David Bodanis' 'The secret house').

Snakes have pits on their head that detect Infrared (re: hunting for mice at night).

Humans have a so-called 'third eye' technically called the pineal gland located under the forehead. Science does not know much about this gland and many suppose its a vestigial remnant. Interestingly, many birds have this gland much closer to the surface of their forehead (possibly to detect the Earth's magnetic field for migration compassing purposes?)

People always talk about cones as being our 'color detectors', but few people know that cones are actually at the back of the retina. Incident light must first travel through many layers of cells in the Plexiform layer of the retina. These cells include (in order of interaction with incident light) Ganglion cells, Amacrine cells, Bipolar Cells, Horizontal Cells AND THEN cones and rods. Many researchers believe Ganglion cells may also act as photoreceptors in addition to the familiar cones and rods. It is also wise to postulate that both Ganglion cells and cones/rods are photoreceptors and their redundancy is part of a fact-checking error correction system. This postulate gains extra credence by the fact that there are many subsystems in the retina that WE KNOW to be utilizers of a fact-checking error correciton system (re: feedback loops in horizontal cells).

If anyone has a question, please ask it, as this is my area of expertise. Finally I won't have to step on Zapper's QM knowledge or SpaceTIger's Cosmology knowledge!

 

[Gokul43201]

I'm not sure I understand your objection Gokul. I don't recall saying perfect reflection makes an object black. Can you elaborate please.

A perfect reflector has an emissivity of zero (from energy conservation and Kirchoff's Law). So, if it emits no light...