Human color sensitivity test...

[Soulhunter]

This (http://forum.doom9.org/showthread.php?s=&threadid=72195) thread gave me the question if this color sensitivity scheme is really right... :rolleyes:

http://img31.photobucket.com/albums/v94/Soulhunter-No.1/HumanColorSensetivity.gif

It tells that human eye is more sensitive @ red color than to blue n' green !!!

But it seems that some ppl are more sensitive to blue color !?!

So to clarify it, here is a small test...


WHICH "A" SHOWS YOU THE MOST UGLY STAIR-STEPPING EFFECT ???

http://img31.photobucket.com/albums/v94/Soulhunter-No.1/Wrong_Upsample.jpg

Note: The green "A" should be less blocky course of YV12's nature...


Bye

[BaronVlad]

the red one in my case...

[Bootsy]

Interesting, the red one for me too.

[unkown]

Red one, of course! That's the reason red is used at traffic-lights and others danger signals.

[LigH]

The reason that red is used in signals is rather, that air absorbs blue light more quickly than red light: the oxygen in the air spreads blue light more quickly, that's also the reason that the sky is blue.

[Andrey]

Heh. But funny thing I must tell:
When I look with one right eye then red and blue A(s) are similiar... :)
What a hell...

[avih]

for me it's blue, just slightly more than the red. green seems fine to me.

BUT this may also be a monitor issue. currently i'm using a resolution just at the top of monitor's caps. so it's slightly blurry (can't see 'clear' pixels with any color).

best test case would be a digital LCD (like in a laptop). desktop LCD are sometimes with analog input, and a screen pixel is not always a monitor pixel. on laptops screen pixel is always monitor pixel (unless you set the desktop resolution to other than the LCD native resolution).

my $0.02

[communist]

Red or blue - seem to look the same to me... I took red ;)

[avih]

thinking about the monitor issue a bit more, i think even a laptop lcd might not give best independant results. as it depends on the arrangement of the RGB sub-cells, and even if the cell's order is identical on each lcd, it still doesn't apply the same for all colors. i.e. the red is left most so it has a different look.

imho, the best test would be on a normal monitor, with the same test image that was posted here, but enlarged x3 or x4 using NEAREST-NEIGHBOUR, such that it keeps the pixelized nature of the image. then we should take few steps back such that the [big] pixels are less noticed, and then vote for which one looks best.

yet another $0.02 (anyone collects those? ;) )

[gatormac]

Blue is much worse to my eyes. I have had Lasik surgery though, so maybe its just a weird side effect!

[Joe Fenton]

Originally posted by LigH
The reason that red is used in signals is rather, that air absorbs blue light more quickly than red light: the oxygen in the air spreads blue light more quickly, that's also the reason that the sky is blue.

Well, to be anal about it, oxygen and nitrogen molecules in the atmosphere scatter all wavelengths of light. This is called Rayleigh Scattering. However, blue light has a much shorter wavelength, so it is scattered more strongly than the other colors (about ten times more than red). This degree of scattering (predominantly blue) makes the color called sky blue.

Because blue light has a higher energy, it is absorded by water vapor and dust more easily than lower energy, longer wavelength colors. Infrared passes right through dust for example and is therefore of great use in astronomy.

[bb]

Under water everything is totally different: the deeper you get, the more the red light vanishes, and everything gets a blue tint. At a depth of 50m there's almost no red left, and if you take photos with a regular film, everything will be blue on it, and I mean blue color, not just a slight tint (believe me, I tried it).

bb

[Uli]

For me it's blue :eek: :confused:
Can't say why though but indeed interesting... :sly:

greetz, Uli

[duartix]

Under water everything is totally different: the deeper you get, the more the red light vanishes, and everything gets a blue tint. Yes I learned it the hard way, in my honeymoon trip to Phi Phi Islands, I did a lot of snorkeling.
Even though the waters were crystal clear, and the film speed was 800 ASA (underwater disposables), most of my pictures went to blue hell. Someone told me I should have used Kodak instead of Fuji. Is there a point in that?
Sorry to be a bit OT. :(

[LigH]

By the way: The only color you may look at for hours without getting crazy, is - blue! Some scientists tried to make probands look at a room in a uniform color; they could only stand blue rooms long enough, any other room made them at least try to close their eyes.

In the nature you won't find many places where you face really uniform colors - except the sky. Any other area most probably has at least some structure. The center of the visible field is less receptive to blue, the outer area instead more.

[Sirber]

Red and Blue have the same stair effect, but red is more apparent.

[mf]

If I were normal it'd have been the most logical red pick, but because I'm weird, it's blue :D.

[echo-kk]

Notebook with dual monitor setup (14" LCD & 19" CRT - both 1024x768x32):

CRT: Red and Blue show the same stair effect
LCD: Blue is definately much worse!

-> I'll vote for BLUE.

(BTW, changing the primary monitor didn't change results)

[Atlantis78]

Hi,
I find the blockiness of the red A easier to notice (almost immediately...), but on a second look, the blue one is worse than the red.

[Neo Neko]

With my right eye red is worse. With my left eye blue is worse. I am slightly color blind in one eye. :p

[pandv]

Very curious,

I am the only one to appreciate more effect in the green?

When I look at the letters, the stair effect is bigger in the green. But, if I look with attention, focusing both eyes in one letter each time, the effect is bigger in the red.

The blue one is ever the best.

pandv

[SeeMoreDigital]

Of course it all depends on your brains ability to process colour.

Many slightly dyslexic people are more sensitive to green. So are more left handed people.

Are you either of the two?

Cheers

[mf]

Actually, I went and took a closer look. You shouldn't use JPEG to compress an image like this. Objectively, red IS less jagged than blue. While with YUV, both blue and red should be equal. I suggest using PNG instead. If you wondered how I managed to look objectively, I split the image to R G and B greyscale images. The red A has a slight blur along the sides of the letter. The blue A only shows the extra detail from the Y channel.

Edit: now this is really strange. I tried reproducing your image with AVS and XviD, but I get the same effect. Shouldn't red and blue be (almost?) equal?

Edit2: Here.
Red: http://mf.creations.nl/avs/ared.png Green: http://mf.creations.nl/avs/agreen.png Blue: http://mf.creations.nl/avs/ablue.png

[Soulhunter]

Originally posted by mf
Actually, I went and took a closer look. You shouldn't use JPEG to compress an image like this.I used JPEG @ 100% quality and 4:4:4 subsampling... ;)

So, if there are compression faults, then only in the luma part !!!

Originally posted by mf
Edit: now this is really strange. I tried reproducing your image with AVS and XviD, but I get the same effect. Shouldn't red and blue be (almost?) equal?
AFAIK they should !!!

Anyway, it explains why you have voted for blue... :D


Bye

[mf]

Originally posted by Soulhunter
Anyway, it explains why you have voted for blue... :D
I've never liked the idea of my eyes being less sensitive to one thing than to another. The fact that I see the color image the same as the objectively split RGB planes, assures me. Maybe this is why my friends insult me for my attention for detail. My eyes aren't human :D.

[Atamido]

As the linked thread would tell you, this is only half of the issue. You should see more jagginess on the red A because your eyes have more red sensors in them allowing you to see a higher resolution of red.

However, the blue and green sensors in your eyes are more sensetive, allowing you to detect different tints more accurately.

This means that efficient color compression will use more red resolution, but devote more color accuracy to blue/green.

[SeeMoreDigital]

It's quite a subjective topic.

Even the colour of a persons eyes (iris). Together with the colour of the white part of their eyes (sclera) can make a difference to how a persons brain reacts to a particular colour.

Sufficed to say. People who were exposed to constant sun, (apart from developing darker skin) developed darker scleras and browner eyes. Which was natures way of protecting their eyes from the 'ultraviolet' spectrum of the sun (before we had sun glasses of course :D). So, such people will automatically see colour differently!

The same can be said for left handed people. As they tend to use parts of their brains that right handed people don't. And people who suffer forms of dyslexia.

In actual fact, the only way to obtain accurate 'colour test' results would be to start this thread again - without a poll. But this time asking users to state: -

* If they are left or right handed.
* The colour of their eyes.
* If they suffer from a form of dyslexia
* The participants 'ethnic' group. But this might be a sensitive issue for some people!

Well there you have it!

Cheers

[pandv]

Many slightly dyslexic people are more sensitive to green. So are more left handed people.

Not, I am not dyslexic or left handed, but I have astigmatism in the right eye (and not lens). So, without concentration, I see primarly with the left eye.

pandv

[mf]

Originally posted by SeeMoreDigital
* If they are left or right handed.
* The colour of their eyes.
* If they suffer from a form of dyslexia
* The participants 'ethnic' group. But this might be a sensitive issue for some people!
* Right handed
* Tricolor
* Language is my strong point
* White

About the "tricolor" thing: the outer ring of my eyes is blue, it's green in the middle, and has an "island" of brown in the center.

[Soulhunter]

Originally posted by mf
About the "tricolor" thing: the outer ring of my eyes is blue, it's green in the middle, and has an "island" of brown in the center.
Originally posted by mf
My eyes aren't human :D.
Explains everything... :D :D :D

[SeeMoreDigital]

Is everybody a nut case on this forum? :D

[Atlantis78]

The red N is the worst!
:D

[ProfDrMorph]

I voted for red. Blue is darker than red and thus in the shown picture you see the edge of the red A much more clearly.

[Soulhunter]

Hmm... Nearly 500 views so far, but only 56 votes !!!

Someone got a clue for this "red n' blue are not equal" thing maybe... :confused:


Bye

[netterpaladin]

I vote for red. When i look really close at the letters, the blockiness of the blue letter is bigger.

This makes me wonder how many of the blue voters touch the screen with their nose when they use their computer...


netterpaladin

[Wolfman]

the higher contrast of the red shows any lack of detail more clearly than the blue but I still voted none. I am much more sensitive to bad spelling

*white is not an ethnic group, northern european is

[Soulhunter]

Originally posted by Wolfman
I am much more sensitive to bad spellingThought -> sense -> sense-tivity... :rolleyes:

Anyway, its fixed now... ;)


Bye

[SoonUDie]

Though all pics have the same luma level, Red appears "brighter" and therefore stands out just a *little* bit more than blue. However, to me this stair-stepping difference is so small that I had to concentrate for a long while just to see any difference at all.

[unmei]

i'm left handed. but the difference seems really marginal to me.

[Mug Funky]

hmm. left handed, blue eyed, 7/8 irish, 1/8 english. probably not dyslexic, but slightly insane.

Mf: you've got real purty eyes :D

i see red as more stair-stepped... i think i'm in the majority here.

[mf]

Originally posted by Mug Funky
Mf: you've got real purty eyes :D
..So the girls say ;).