Are there such things as pure colors?
 

What I mean is - is there a shade of, say, red, that's considered to be pure red? I know there's crimson (which I'm guessing Eublet considers to be pure ;):D), scarlet, cardinal, burgundy, etc. But is there a scientific way to determine whether or not any shade of color is the pure version of that particular color? In other words, this blue is the real blue. Or is there such a thing?

Yes.

lowsound

In the printing world they use:

YELO-yellow
MAGENTA-red
CYAN-blue
BLACK-black

For 4 color process printing. They are the primary colors and are combined to get you the greens, purples, greys, orange & warm reds, cold tones.

In this case, YELO, CYAN, MAGENTA are pure with no other coloration. In a sense, they are as pure as man-made can get. Paint experts have their methods for developing these tones as well. But these create most of the hues you see in a PANTONE or paint color swatch books you see at Home Depot, etc.

There are processes, chemical & otherwise to augment these colors to get those Ferrari reds, those Bugatti blues, the Mopar Greens and Plum Crazy, etc.

For physics, no. Colors are defined by a range of frequency. If you're in the range, you're in the color.
For industry standards, there are pure colors but the choice is arbitrary, just like an A440 is only a pure A because we choose it to be so.

And don't forget, primary and secondary colours are different for paints/pigments and light. Colour by addition or colour by subtraction.

Fundamentally though, whatever colour label you choose, you are effectively just giving a name to that particular specific energy/frequency/wavelength of a stream photons that stimulate the important bits on your retina.

There's three kinds of colour receptor cell in the eye, each having a different centre frequency. You could say that "the reddest red" corresponds to the centre frequency of the lowest frequency receptor, which according to Wikipedia is 564–580nm

That's cool, except that the spectra of the three receptors vary from individual to individual, even for those with "normal" color vision.

Sure, it's going to be an median number. Reading up on WP there's even some folks who have four receptor types.

If we go to individuals then we have to deal with that whole qualia thing too. Is your "red" the same as my "red" or if I were inside your mind would it look "green" to me? etc. etc....

My retina, or your retina? I've always wondered if my blue is your blue..... There's really no way to verify it is there?

Trippy dude.....

Seeing as everyone sees color differently, I'd say no.

hahaha I always wondered the same thing ...

I have always wondered that with food and smells. Does coconut taste the same to you as it does to me? If so, then you are crazy because stuff is nasty!

lowsound

Because people will see purity of color differently, I was wondering if there was an instrument that can detect if a color is pure - not too dark or too light, and not mixed with anything else (I'm thinking primary colors here). Or can it even be scientifically detected? Is there such a measure? Googling it didn't help.

BTW, what brought about the question was me seeing a bright red car and thinking, "That's not burgundy, crimson, or whatever...that's RED!" It wasn't because of personal preference; I like darker shades of red.

Hi.

In nature: No.

In sciences and technology: Yes.

And even in science, it's a matter of defining the frequency range as have been mentioned earlier.

LEDs and lasers are the most common way to produce "pure" colours, no other means come even close.

The emissivity of a material varies greatly depending on the conditions, so materials can only be said to be pure in colour if the conditions are defined as well.

A spectrometer reading will reveal the wavelenght(s), intensities and their relations involved.

Regards
Sam

The whole qualia thing was an attempt to refute physicalism by smothering it in sophistry.

Most normal-sighted people can agree on (for instance) what to look for if they are sent into a garden to collect some ripe tomatoes from amongst a bunch of unripe ones.

But the thing is, do they all see it the same? If you are told "This is red.", all of your life, then whatever you see is red whether or not it is the same as what others see.

Of course, most likely we all see it the same. But how could we tell?

"Was" seems to imply that you believe that the debate is closed. I'd disagree - IMO, the questions are still both open and interesting. (But then, I regard the Dennett that I've read so far as persuasive evidence that zombies can exist and write books).

Sure, but that's nothing to do with qualia. That's names and their referents in the objective world. Whether the same name points to the same subjective experience in different minds is nothing to do with that case.

Thee is however pure black and pure white.

Thanks, Sam. I figured there was a scientific way to go about it. And people can still decide for themselves if they consider the color they're viewing at the moment to be pure. Subjective vs. objective.

In television there is something called Super black which is a color most current graphic software and desktop computers cannot generate. Super black is a color used in the SMPTE color bars and it has historically been used as a matte to key out and leave what image was not super black on screen. This would be used to make what is referred to as an ID or lower third, much like what you see when someones name is displayed below on screen. Super black cannot be generated by macs or pc's and had only been made using expensive proprietary graphics machines such as a Quantel Paintbox. We no longer need super black for keying images on air and it may be why we don't hear much about it these days working with on air graphics.