Medical Colors that we could normally see

[gerben]

Spectral content just means the wavelengths and the intensity of those wavelengths. To describe the spectral content of a scene you would have to describe the wavelengths (and their intensities) of the light coming from every point in the scene.

This is quite complicated, it depends on the direction from which you look onto the scene and on (the spectral content of) the light that illuminates the scene, but nowadays there are devices that can measure this.

The spectral content describes the physical aspects of the light coming from the scene. However, humans experience this as a scene filled with colors, that is what I meant with "chromatic situation": in human beings the physical situation (i.e. the spectral content of the scene) gives rise to a chromatic interpretation (i.e. a colorful scene).

 

[Moonbear]

Somebody said this:

"list all the different "chromatic situations" (i.e. descriptions of the spectral content of the scene)"

What does it MEAN though? How would you do that? etc

thanks

This is from the color thread:
https://www.physicsforums.com/showthread.php?t=88705&page=2&pp=20

If you're going to quote someone here, use quote tags and identify the person/source you're quoting (in this case, the quoted text was written by Gerben). There's no need to start a new thread every time you have a question about someone's reply in a previous thread; the point of a discussion is you can ask them to clarify or explain in the same thread. Why have someone else try to explain what a member meant in a reply when you can ask them directly in the thread they posted it in? When you quote it out of context, you lose meaning. In the proper context, the answer to your second question was partially answered in the other two sentences of Gerben's reply.

You would have to determine which of those situations give the same color and give those the same color-name. Whether any two give the same color could be established by asking human subjects.

It would be a ridiculous undertaking though. The other replies in that thread already pointed out how difficult it would be. You could come up with A list, but I doubt you could ever come up with a comprehensive or complete list.

 

[Genecks]

It would be a ridiculous undertaking though. The other replies in that thread already pointed out how difficult it would be. You could come up with A list, but I doubt you could ever come up with a comprehensive or complete list.

Because of that from lack of digital device being able to go through the complete range of analog color, would that be?

Digital devices have their limits.

 

[hypnagogue]

Please note that the last four posts in this thread were originally posted in a separate thread titled "phrase." Since "phrase" was merely a continuation of the discussion started in this thread, I have merged the two together.

 

[hypnagogue]

It would indeed be impractical to try to exhaustively list all the chromatic situations one could possibly come across. For instance, suppose we take a very simplified situation-- suppose we want to find the number of chromatic situations one could display on a computer monitor. Suppose we ignore the environment in which the computer monitor is viewed, and suppose that we hold viewing distance, lighting conditions, and angle of view constant. Suppose the computer monitor has a 1024x768 resolution, with each pixel capable of displaying one of 16,777,216 colors. (These are fairly standard settings for a computer monitor.)

So what can our monitor display? Since it's at 1024x768 resolution, it has 1024 * 768 = 786,432 pixels. Each of these pixels can display one of about 16.8 million colors, so the range of possible displays on the monitor is

786,432 pixels * 16,777,216 colors/pixel = 13,194,139,533,312 chromatic situations!

So even in a highly constrained and artificial scenario like the one outlined above, for a single computer monitor, there are over 13 trillion chromatic situations. Of course, that number balloons even larger if we take into account lighting conditions or the visual content of the surrounding environment, etc. So, no, it's probably not a good idea to bother trying to come up with all the possible chromatic situations.

 

[NeedBioInfo]

My dad said this:

There are 16,777,216 ^ 786,432 chromatic situations, where "^" means* "to the power of".* Since there are only about 10 ^ 80 atoms in the* universe, you would need a much larger universe in order to create a* list long enough to list all the chromatic situations.

so I'm looking for info about that...
thanks

 

[hypnagogue]

whoops, sloppy mistake on my part. Your dad did the calculation correctly.

What further information can you want though?

 

[NeedBioInfo]

I guess I just wanted to check that that was correct, and, if it wasn't, to find out about it

anyways, thanks

 

[hitssquad]

Hyperphysics and the C.I.E. color space

Could somebody give me a list of all the colors that we could normally (Except for when we're color-blind, etc) perceive?

Also, could somebody give me a list of all the different shades, etc (Eg an illustrated list) that we could normally (Except for when we're color-blind, etc) perceive? Or at least, for example, a numerical amount of the shades that we could normally perceive?

The best information you can get on this is at Hyperphysics (I think you might want to be sure to follow all of the links from this primary link):
hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html

 

[fuzzyfelt]

The best information you can get on this is at Hyperphysics

Great link!
Especially if the aim of this thread is, as it says, perception of colour.
If the thread is for painting then how this perception is translated by pigments is also important.

 

[fuzzyfelt]

I felt I had better correct my mistake.

Thanks to this thread my understanding of pigment colour theory has undergone a much needed (though still learning) overhaul -

that the artist's traditional colour wheel has been considered incorrect since 2004, and a new (though considered fallacious) theory replaces the pigment primaries of red, yellow and blue, with subtractive 'primaries' yellow, cyan and magenta - http://www.handprint.com/HP/WCL/color5.html ;

or another view that involves primary pigments of red, yellow, blue and green - http://plato.stanford.edu/entries/color/.

Thanks for making this thread, as it (finally) helped me question some things I had taken for granted.