Colour

Split from 'Non-human animals as moral subjects'

on fundamental matters such as existence, knowledge, values, reason, mind and ethics.

Moderators: Calilasseia, ADParker

Re: Colour

#841  Postby GrahamH » Aug 18, 2017 11:53 am

DavidMcC wrote:Incorrect, Graham. I think you'll find that those words first appeared in romansh's deliberate misquote, not in my actual post that he claimed to be quoting.
I don't see the point of this side-track, unless it's just yet another attempted provocation, so I will try not to waste any more time on it, OK.


You really should try to stop making these idiotic accusations against people, especially when the circumstances have just been explained to you and have nothing to do with Romansh.
Why do you think that?
GrahamH
 
Posts: 19871

Print view this post

Ads by Google


Re: Colour

#842  Postby DavidMcC » Aug 18, 2017 11:56 am

I see you are continuing the garbage. I will ignore this thread until it improves (IF it ever does).
May The Voice be with you!
DavidMcC
THREAD STARTER
 
Name: David McCulloch
Posts: 14913
Age: 66
Male

Country: United Kigdom
United Kingdom (uk)
Print view this post

Re: Colour

#843  Postby romansh » Aug 19, 2017 10:23 pm

GrahamH wrote:
From the 'blue-grey' pixels of course. You can't make grey without red photons.

BTW the light sources may not be perfectly monochromatic. For most TFT displays it will be white LEDs or electroluminescent lighting which are far from monochromatic shining though bandpass filters for RG & B that are tens of nm wide.


OK what I am trying to ask is when David said:
DavidMcC wrote:
GrahamH wrote:Yes, the strawberries look red ( a rather bluish-red). The very reason that picture has been so widely circulated is because people see red. Ditto for the black/blue/white/gold dress where people are convinced it is one or the other colour combination.
I think it is more because the background is so in-red more than an internal model of what colour strawberries should be.

They still look grey-blue to me, I'm afraid, not in the least red.

where did the grey come from on the strawberry picture for David?
"That's right!" shouted Vroomfondel, "we demand rigidly defined areas of doubt and uncertainty!"
User avatar
romansh
 
Posts: 2699

Country: BC Can (in the woods)
Print view this post

Re: Colour

#844  Postby The_Metatron » Aug 20, 2017 12:07 am

Or, is it possible that our observer is somewhat color blind? Less red sensitivity than others? It's something that could be quickly tested, and might be interesting.


Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.
User avatar
The_Metatron
Moderator
 
Name: Jesse
Posts: 20591
Age: 56
Male

Country: United States
United States (us)
Print view this post

Re: Colour

#845  Postby romansh » Aug 20, 2017 4:23 am

The_Metatron wrote:Or, is it possible that our observer is somewhat color blind? Less red sensitivity than others? It's something that could be quickly tested, and might be interesting.


I don't think so Metatron. In fact David is closer to seeing the "truer" colour. I also see a "greyness" to that strawberry picture, but more so on the background. But supposedly that picture is supposedly free of red pixels.

While all this is interesting it is not what the thread was originally about. ie the illusory nature of colour in general.
"That's right!" shouted Vroomfondel, "we demand rigidly defined areas of doubt and uncertainty!"
User avatar
romansh
 
Posts: 2699

Country: BC Can (in the woods)
Print view this post

Re: Colour

#846  Postby scott1328 » Aug 20, 2017 7:55 am

it seems that that picture is exactly what this thread is about.
User avatar
scott1328
 
Name: Some call me... Tim
Posts: 8483
Male

United States (us)
Print view this post

Re: Colour

#847  Postby GrahamH » Aug 20, 2017 5:04 pm

romansh wrote:
The_Metatron wrote:Or, is it possible that our observer is somewhat color blind? Less red sensitivity than others? It's something that could be quickly tested, and might be interesting.


I don't think so Metatron. In fact David is closer to seeing the "truer" colour. I also see a "greyness" to that strawberry picture, but more so on the background. But supposedly that picture is supposedly free of red pixels.

While all this is interesting it is not what the thread was originally about. ie the illusory nature of colour in general.


"truer colour"? What colour do you think those actual strawberries were? They were red, of course, not grey or blue. Colour constancy allows us to correctly identify things by colour even in unusual lighting conditions. Someone who can't do that is at a disadvantage.
Why do you think that?
GrahamH
 
Posts: 19871

Print view this post

Ads by Google


Re: Colour

#848  Postby GrahamH » Aug 20, 2017 5:05 pm

scott1328 wrote:it seems that that picture is exactly what this thread is about.


I agree.
Why do you think that?
GrahamH
 
Posts: 19871

Print view this post

Re: Colour

#849  Postby romansh » Aug 20, 2017 6:09 pm

GrahamH wrote:
"truer colour"? What colour do you think those actual strawberries were? They were red, of course, not grey or blue. Colour constancy allows us to correctly identify things by colour even in unusual lighting conditions. Someone who can't do that is at a disadvantage.

So if I were in a room painted with monochromatic green and blue illuminated with monochromatic blues and green could my mind be tricked into seeing red where there was none?

But ultimately it does not answer the question whether the surface of real life strawberries have the colour I perceive and does it even make sense to think that the strawberries are actually red. The physics here is not at issue. The redness of the strawberry is completely a product of my mind, bearing in mind photons around 64o nm are striking my retina, photochemical reactions are occurring in my cones, charge is being transferred down my optic nerve, the signal/charge is being processed in my brain and I perceive a redness.

Sure my perception is correlated with the surface properties of the strawberry, but that is all.
"That's right!" shouted Vroomfondel, "we demand rigidly defined areas of doubt and uncertainty!"
User avatar
romansh
 
Posts: 2699

Country: BC Can (in the woods)
Print view this post

Re: Colour

#850  Postby GrahamH » Aug 20, 2017 6:34 pm

romansh wrote:Sure my perception is correlated with the surface properties of the strawberry, but that is all.


Why not "that is everything"? That is how you distinguish ripe strawberries from unripe and you can do it even in bad light. What else are you seeking?
Why do you think that?
GrahamH
 
Posts: 19871

Print view this post

Re: Colour

#851  Postby GrahamH » Aug 20, 2017 6:40 pm

romansh wrote:
GrahamH wrote:
But ultimately it does not answer the question whether the surface of real life strawberries have the colour I perceive and does it even make sense to think that the strawberries are actually red.


I thought that was settled. 'redness' is a construct of your brain, not something stuck to the surface of fruit or buses. Your 'qualia' aren't on the fruit. It doesn't even make sense to pose the question. Your qualia reflects the spectral characteristics of the object and it is accurate and reliable in most cases, even adverse conditions. Yes the strawberries are actually red not green or blue or grey (don't eat those strawberries).
Why do you think that?
GrahamH
 
Posts: 19871

Print view this post

Re: Colour

#852  Postby romansh » Aug 20, 2017 7:47 pm

GrahamH wrote:
romansh wrote:Sure my perception is correlated with the surface properties of the strawberry, but that is all.


Why not "that is everything"? That is how you distinguish ripe strawberries from unripe and you can do it even in bad light. What else are you seeking?

Pragmatically I am not seeking anything from colour perception. This was purely philosophical discussion.

Again I was pointing out to where you and Scott agreed that what this thread was about. It may have morphed to what is more traditionally considered an illusion, but was no the original intent. So in this sense we are agreed.
"That's right!" shouted Vroomfondel, "we demand rigidly defined areas of doubt and uncertainty!"
User avatar
romansh
 
Posts: 2699

Country: BC Can (in the woods)
Print view this post

Re: Colour

#853  Postby scott1328 » Aug 20, 2017 11:28 pm

Your quest for final answers is bewildering to me. In this thread you ask: is the bus "truly" red?

In the free will thread you ask. But is it "truly" free will.

What answer can satisfy you other than the answer you already have concluded upon?

In this thread you seem to reject any definition of color unless it builds "illusory" into its definition.

In the free will thread you reject any definition unless that definition renders free will incoherent, or impossible.

You don't seem to want discussion just agreement.
User avatar
scott1328
 
Name: Some call me... Tim
Posts: 8483
Male

United States (us)
Print view this post

Re: Colour

#854  Postby DavidMcC » Aug 26, 2017 4:22 pm

romansh wrote:
GrahamH wrote:
romansh wrote:Sure my perception is correlated with the surface properties of the strawberry, but that is all.


Why not "that is everything"? That is how you distinguish ripe strawberries from unripe and you can do it even in bad light. What else are you seeking?

Pragmatically I am not seeking anything from colour perception. ...

You don't seek anything from colour perception? Come again? That does not make sense. Most of us were discussing the usefulness of colour perception, but you don't seem to care what the phrase even means! :scratch:
May The Voice be with you!
DavidMcC
THREAD STARTER
 
Name: David McCulloch
Posts: 14913
Age: 66
Male

Country: United Kigdom
United Kingdom (uk)
Print view this post

Re: Colour

#855  Postby romansh » Aug 26, 2017 4:44 pm

DavidMcC wrote:Most of us were discussing the usefulness of colour perception, but you don't seem to care what the phrase even means! :scratch:

Yes and it is a continuous derail of the topic.
"That's right!" shouted Vroomfondel, "we demand rigidly defined areas of doubt and uncertainty!"
User avatar
romansh
 
Posts: 2699

Country: BC Can (in the woods)
Print view this post

Ads by Google


Re: Colour

#856  Postby The_Metatron » Aug 27, 2017 3:09 am

The wiki article on color vision is illuminating, with plenty of tangent links to follow.


Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.
User avatar
The_Metatron
Moderator
 
Name: Jesse
Posts: 20591
Age: 56
Male

Country: United States
United States (us)
Print view this post

Re: Colour

#857  Postby DavidMcC » Aug 27, 2017 1:39 pm

Metatron, the Wiki article you linked is flawed, in particular because of this graph:
Image
There are two issued with this:
1. The gaussian envelope curve implies that the brain has infomation about the wavelengths of light falling on the retina, when all it has is the three (for trichromats, at least) cone cell type signals.
2. The preponderance of turquoise in the peak, when yellow is the brightest colour (having the strongest overall cone cell signal, due to the high overlap between the MW and LW cone cell response , as shown in another graph on the page (one that actually is correct).
I tried asking for scientific references for the "color sensitivity" graph, but none were forthcoming. I strongly suspect that it came out of someone's head, and that someone had a more artistic than scientific bent, the subject being of great interest to artists.
3. Note also that there is almost no green in the graph, its space being taken over by turquoise.
May The Voice be with you!
DavidMcC
THREAD STARTER
 
Name: David McCulloch
Posts: 14913
Age: 66
Male

Country: United Kigdom
United Kingdom (uk)
Print view this post

Re: Colour

#858  Postby DavidMcC » Aug 27, 2017 2:48 pm

BTW, here's a better rainbow than the background to that strange graph above:
Image
(From www.workwithcolor.com)
May The Voice be with you!
DavidMcC
THREAD STARTER
 
Name: David McCulloch
Posts: 14913
Age: 66
Male

Country: United Kigdom
United Kingdom (uk)
Print view this post

Re: Colour

#859  Postby SkyMutt » Sep 01, 2017 3:30 pm

Regarding the strawberry image, I wondered about the actual color of the pixels making up the image. Though there are no purely red pixels in the strawberries as far as I've been able to discover, there are plenty of pixels that have a reddish tinge. The detail below is from the halved strawberry with the slice facing away from the camera, near the tip.

Image
Magnified detail

Image
Black rectangle indicates location of detail
Serious, but not entirely serious.

"The charm of a man is measured by the charm of the women who think he is a scoundrel."
— H. L. Mencken
User avatar
SkyMutt
 
Posts: 833
Age: 60
Male

Country: United States
Print view this post

Re: Colour

#860  Postby GrahamH » Sep 01, 2017 3:57 pm

Zoomed
Strawberry_Zoom.jpg
Zoomed
Strawberry_Zoom.jpg (41.28 KiB) Viewed 1994 times


Just the tip of the reddest strawberry as identified by SkyMutt, surrounded by white
Strawberry_Tip_onWhite.jpg
Strawberry_Tip_onWhite.jpg (33.91 KiB) Viewed 1995 times



That tip colour filling a big square.
Strawberry_Tip.jpg
Strawberry_Tip.jpg (31.67 KiB) Viewed 1995 times


We need the context cues for colour constancy to allow us to see the 'proper colours'.

As SkyMutt's expanded image shows it doesn't take much to see it as red.
Why do you think that?
GrahamH
 
Posts: 19871

Print view this post

PreviousNext

Return to Philosophy

Who is online

Users viewing this topic: No registered users and 2 guests