White light

[Asimov]

Petrushka: Swansont nailed it. Some do have better eyes for color vision. Tetrachromats have 4 instead of 3 type cones! Guys need not apply. It is rare and only in those with XX chromosomes.They see more colors than others. One of evolution's experiments. An interior decorators' nightmare.One day we may have many more type cones. Doubt it. 3 works good enough. 4 is a crowd.

 

There may be other ways of getting clues to differentiate frequencies. Polarization. This may be up your alley.Octopi are said to be quite color blind, likey based on eye anatomy. BUT they change colors to match their environment. Octopi are very good at discerning polarization differences. They may see only black,grey and white but because of polarization they might discern the slightest contrasts between frequencies and access colors that way..This info could tell them what colors to change to in order to fool animals with color vision! .

If an octupus can see colors based on polarization they wouldnt technically be color blind but wouldnt necessarily see colors the same as us.

[John Cuthber]

 

What I'm trying to say is that the white we see is limited by our limited perception (10 million colors). If we had a better sensor (eye) capable of tapping say, 20 million colors what we interpret as white would possibly not be so.

You are mixing two different things here.

We may well be able to distinguish ten million colours, but I doubt we can distinguish a thousand wavelengths.

500nm looks pretty much the same as 501nm.

But 500 nm at 1 watt per metre squared an be distinguished from 500 nm at 0.9 watts per metre squared.

the colours aren't just peak wavelengths but relative intensities too.

[Asimov]

Good point John. We are quite specific when we refer to frequencies but somewhat broader with our color interpretations.In addition to the primary colors interpretations, Hue, lightness, temperature and contrast determin color perception as well. A 50% saturated color looks different next to the 25% saturated. Is polarization a small factor in humans? Works for Octopi. You saw how colors can appear to change with after images despite no change of frequency. How many colors can there be? As many as we can percieve. Open season on colors.

 

What is your favorite color?.Mine is blue, always has been, why? Bet blue looks different to me than you. Bet we never know. Why on earth did the Minn. Vikings pick purple. My H.S, colors were blue and gold. Any turquoise and pink team color themes?

 

Why does red look better on small sporty cars. Ever see a red limo? How many bright orange pickups do you see? Not in this here neck of the woods. Why does no color look good on an Edsel. It didnt sell well in any color. Beauty and color is in the view of the beholder.

http://vanseodesign.com/web-design/hue-saturation-and-lightness/

[swansont]

Is polarization a small factor in humans?

 

 

Not really. Some humans can detect polarization via observing Haidinger's brush, but otherwise there's no effect

 

https://en.wikipedia.org/wiki/Haidinger%27s_brush

[John Cuthber]

The thing is that colour is entirely subjective so "white" means different things to different people at different times.

 

 

BTW, if you want to be pretentious about the plural of octopus, it's "octopodes".

If you are writing in English, it's "octopuses" and the one thing it never was nor will be is "octopi".

 

Feel free to discuss this- in a different thread.

Edited September 19, 2015 by John Cuthber

[petrushka.googol]

The thing is that colour is entirely subjective so "white" means different things to different people at different times.

 

 

Color is subjective but light as a physical entity is not. I find that an anomalous paradox of sorts....

[Asimov]

I prefer english but octopodes sounds impressive. Whom is cooler than who also.

 

Thanx Swansont about Haidengers brush. I forgot that long ago. I Only started thinking about polarization and color perception in humans as octopodes may use it in color perception or even vision perception. Unproven I think but viable.I cant see how it would work or be needed in humans but I wonder. I do think it may be involved in our vision perception to some small degree. I have various pseudoisochromomatic plates and polarized stereopsis tests and used polarized light and red green filters and viewing polaroid filters at various angles today with no results I can see other than increasing or decreasing the darkness. Duh. I wasnt expecting anything but it was fun.

 

Looking down the highway we see reflections of the sky on the highway that look like water. The light is polarized though and we can eliminate this effect with polaroid glasses. I use them canoeing to see rocks and fish.

 

The Gannet is a diving fishing bird whos eyes adapt instantly to underwater. Wonder if thay have polaroid vision. Corneas are very transparent because the fibers have a latice arrangement that is spaced such that visible wavelengths slither around and under the fibrles and pass through almost totally. Clearer than glass. An inexpensive evolutionary change of this lattice arrangement would polarize light. My speculation, no sources unless you can find some. Would have loved to do my Doctorate paper on something like this.All we had were monkeys, rabbits and mice and there was no internet to google.No Gannets.

[Sensei]

I Only started thinking about polarization and color perception in humans as octopodes may use it in color perception or even vision perception. Unproven I think but viable.I cant see how it would work or be needed in humans but I wonder. I do think it may be involved in our vision perception to some small degree. I have various pseudoisochromomatic plates and polarized stereopsis tests and used polarized light and red green filters and viewing polaroid filters at various angles today with no results I can see other than increasing or decreasing the darkness. Duh. I wasnt expecting anything but it was fun.

 

1) look at water (reflecting some things) through polarization filter, and start rotating it.

You will notice how reflection is disappearing.. And you will be able to see what is below water surface more easily.

 

2) point laser at polarization filter, in darkness, or even better under water (blue laser the most visible). You will see two beams of laser coming from polarization filter. One is reflected, second one passed through filter.

It can be repeated multiple times with multiple filters in row. If polarization filters are always rotated the same angle (pointing up f.e.), reflected beams will be each step less and less powerful, while beam that passed through will be visibly more powerful than reflected.

Edited September 20, 2015 by Sensei

[Strange]

The thing is that colour is entirely subjective so "white" means different things to different people at different times.

 

 

BTW, if you want to be pretentious about the plural of octopus, it's "octopodes".

If you are writing in English, it's "octopuses" and the one thing it never was nor will be is "octopi".

 

Feel free to discuss this- in a different thread.

 

You make two good points here. I accidentally hit the "-1" button so I apologize for that. (I have done this several times - I need to be more careful!)

 

Color is subjective but light as a physical entity is not. I find that an anomalous paradox of sorts....

 

Everything we perceive is subjective (by definition). The cause of those subjective perceptions is (non-subjective) reality. So no paradox at all; it is just the way, the only way, we can perceive the universe around us.

[Mordred]

I removed the neg point on that post

[John Cuthber]

I removed the neg point on that post

Thanks

[Strange]

I removed the neg point on that post

Thanks!