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Your eyes suck at blue

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Re: Your eyes suck at blue

#31

Post by evilduck »

sliverstorm wrote: post #21
corysama wrote: post #14

Earlier quoted context omitted.

I do know a little about human color perception. Although the author's example is flawed, his argument does stand. Human eyes are much less sensitive to details in blue compared to green and red. Here's the best illustration I can find in a minute's googling: http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/OWEN... from http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/OWEN... This shows up in the Red-vs…

> Human eyes are much less sensitive to details in blue compared to green and red IIRC our strength with green is why many night-vision systems use only green. It has other benefits such as not killing your night vision, but when you take the darkness of the night and remove the red and blue components, you can see better. Once again, IIRC.

Furthering this, I've also read (but can't cite off hand) that it's evolutionary.

A good chunk of the world is green, ripeness of fruits and vegetables can be determined at a distance by detecting green, and moonlight reflecting off of stuff will likely be green more than other colors, enabling the cones to do some of the night vision work besides the rods. Conversely, the only major blue things in nature tend to be the sky and flowers, neither of which provide a significant survival advantage. Interestingly, some women may actually be tetrachromats, giving them incredible ability to differentiate reds.

Also...I can't recall the exact reason, but we have trouble focusing on blues as well (wavelengths maybe?). If you have one nearby, one night go park near the middle of the lot of a Petsmart, which has a bright red/blue sign. Look at the sign while moving your head left and right, the blue letters will appear to move while the red remain stationary.

Re: Your eyes suck at blue

#32

Post by dgreensp »

tensor wrote: post #29
jemfinch wrote: post #26

Earlier quoted context omitted.

You're wrong. No, you can't just split a picture into three channels and say "Hey, blue looks dark," because blue might actually be dark. You can, however, make a picture grayscale, then turn that same grayscale picture into redscale, greenscale, and bluescale. The luminance would be exactly the same for every pixel, the only difference would be the pixel's color. I did that, in fact, and you know what? Your eyes rea…

Actually, your conclusion is incorrect. While there are fewer receptors for blue, each is much more sensitive. All you demonstrated is that the sRGB color model is blue deficient. See http://en.wikipedia.org/wiki/Color_vision and http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-... for details. In particular, I'd like to draw your attention to the CIE 1931 chromatic diagram in the wikipedia link. This is s…

Agreed. If red=255 looks brighter on your monitor than blue=255, well, that's how the monitor was designed!

Re: Your eyes suck at blue

#33

Post by jiganti »

docgnome wrote: post #12
jarin wrote: post #5

That is pretty neat, although I'm not sure I understand all the outrage. "THE DVD FORUM IS STEALING OUR PIXELS!!" If your eye doesn't notice the difference, are you being "bilked"?

I think it's the same situation as so called "audiophiles" who spend large amounts of money on gold cables and ultra expensive headphones. They may or may not be able to tell the difference but the knowledge that their 10000USD headphones produce a slightly large range of sound than the 100USD pair makes them believe that the more expensive headphones are worth it. In the same way you could probably sell some sort of…

I'm not sure it would work if no one could tell the difference, and I'll cite your example of the audiophiles.

Many people are overpaying for sound equipment that would sound no different to them than stuff half the price, but the fact that there are people that can tell the difference, who talk about that difference constantly, keeps the deluded part of the market in the dark. These people will never do some sort of double-blind test to identify whether or not they can tell the difference, but since there were originally people who could recognize it, others started to follow blindly. There has to be some starting off point before the masses buy into the hype.

Re: Your eyes suck at blue

#34

Post by [deleted] »

bradleyland wrote: post #7

Ugh. We don't have an entirely clear picture of how our eyes physically detect color, much less how we perceive it, but there are serious problems with the argument the author makes here. You cannot simply take a color photograph of a scene, split it in to three channels, then point out that the blue channel is "dark and contains less detail" as evidence of our inability to perceive the color blue. The fact is that t…

[deleted]

Re: Your eyes suck at blue

#35

Post by iwr »

Low blue sensitivity may be due to the eye's lens being opaque to UV (very bright blue). This is for good reasons because then daylight illumination would be painful and cause retinal damage over time.

The blue color receptor can actually capture a wider range blues and low UV shades. People who had cataract surgery (which replaces the defective lens with an artificial one) may see into these deeper shades of blue if they received an older style of implant.

http://www.guardian.co.uk/science/2002/may/30/medicalscience...

Re: Your eyes suck at blue

#36

Post by confuzatron »

bradleyland wrote: post #13
confuzatron wrote: post #10

Earlier quoted context omitted.

Lots of text there, and you certainly sound confident, but I tried an experiment, and it confirmed the claims of the article. I used Paint.NET, loaded in an image, copied it to three layers. Adusted each layer to be a single colour channel, then changed each of the layers to 'Additive' mode. Pixellating the blue layer - I could perceive at most some 'colour blotching', but no real loss of 'sharpness' Pixellating the…

The additive color model isn't exactly the same as the layer modes you'll see in image editing apps. This "mode" affects how the values of the current layer are applied to the layers below it. The normal mode is to replace the values below. When you switch to additive, the RGB channels from the current layer are "added" to the values of the layer below. This is entirely different than the concept of the additive colo…

I'm sorry, but this is all irrelevant waffle.

The issue is that the human eye is less able to distinguish detail in the blue spectrum, as the article (and a quick test) shows.

(Blimey, I just noticed your first comment got 22 votes! Apparently irrelevant waffle gets upvoted on HN, if it sounds confident)

Re: Your eyes suck at blue

#37

Post by confuzatron »

ramidarigaz wrote: post #11
confuzatron wrote: post #10

Earlier quoted context omitted.

Lots of text there, and you certainly sound confident, but I tried an experiment, and it confirmed the claims of the article. I used Paint.NET, loaded in an image, copied it to three layers. Adusted each layer to be a single colour channel, then changed each of the layers to 'Additive' mode. Pixellating the blue layer - I could perceive at most some 'colour blotching', but no real loss of 'sharpness' Pixellating the…

How do you know the unnoticeable pixellation of the blue isn't an artifact of the way blue is displayed by your screen?

So, my screen doesn't display blue in a way that pixellation is visible to the human eye, and this is somehow not an issue with the human eye how?

Re: Your eyes suck at blue

#38

Post by bradleyland »

jemfinch wrote: post #26
bradleyland wrote: post #7

Ugh. We don't have an entirely clear picture of how our eyes physically detect color, much less how we perceive it, but there are serious problems with the argument the author makes here. You cannot simply take a color photograph of a scene, split it in to three channels, then point out that the blue channel is "dark and contains less detail" as evidence of our inability to perceive the color blue. The fact is that t…

You're wrong. No, you can't just split a picture into three channels and say "Hey, blue looks dark," because blue might actually be dark. You can, however, make a picture grayscale, then turn that same grayscale picture into redscale, greenscale, and bluescale. The luminance would be exactly the same for every pixel, the only difference would be the pixel's color. I did that, in fact, and you know what? Your eyes rea…

I edited my post within 15 minutes of posting, because I re-read it and realized that it came across that I was challenging the assertion that our eyes are less sensitive to blue. A fact I wasn't sure of either way (but have since learned the facts about). See tensor's and corysama's excellent posts below that contains some great links.

I said plainly in my edit, "My main point is that his argument is flawed, not his assertion." No need to get snarky.

Re: Your eyes suck at blue

#39

Post by jemfinch »

bradleyland wrote: post #38
jemfinch wrote: post #26

Earlier quoted context omitted.

You're wrong. No, you can't just split a picture into three channels and say "Hey, blue looks dark," because blue might actually be dark. You can, however, make a picture grayscale, then turn that same grayscale picture into redscale, greenscale, and bluescale. The luminance would be exactly the same for every pixel, the only difference would be the pixel's color. I did that, in fact, and you know what? Your eyes rea…

I edited my post within 15 minutes of posting, because I re-read it and realized that it came across that I was challenging the assertion that our eyes are less sensitive to blue. A fact I wasn't sure of either way (but have since learned the facts about). See tensor's and corysama's excellent posts below that contains some great links. I said plainly in my edit, "My main point is that his argument is flawed, not his…

My apologies, I missed that edit (somehow, despite my posting time).

Re: Your eyes suck at blue

#40

Post by bradleyland »

jemfinch wrote: post #39
bradleyland wrote: post #38

Earlier quoted context omitted.

I edited my post within 15 minutes of posting, because I re-read it and realized that it came across that I was challenging the assertion that our eyes are less sensitive to blue. A fact I wasn't sure of either way (but have since learned the facts about). See tensor's and corysama's excellent posts below that contains some great links. I said plainly in my edit, "My main point is that his argument is flawed, not his…

My apologies, I missed that edit (somehow, despite my posting time).

Happens to me all the time :) I have to read everything twice.
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