[confuzatron]

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 green layer - pixellation was easily visible.

Pixellating the red layer - the effect was somewhere in between.

You should give it a try. Here's my test Paint.NET image file with the layers all set up for you:

http://dl.dropbox.com/u/714931/bluejay.pdn

[bradleyland]

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 color model.

There are two broad color model types: additive and subtractive. Additive color models (like RGB) "add" color to arrive at white. Subtractive color models (like CMYK) "subtract" color to arrive at white. In the RGB additive color model, we most frequently refer to the primary colors, RGB, but the secondary colors (cyan, magenta, and yellow) are equally important. The primary colors are the result of raising only one channel to full luminance while all the others are at zero. The secondary colors are produced by raising all channels to the maximum, then dropping one channel to zero. The secondary color for the blue channel is yellow.

The consequence of this is that you can't simply pixelate the blue channel in an additive model RGB image and claim this proves a lack of ability to perceive color in the blue light spectrum, because the alteration of the primary color will inevitably affect the distribution of the secondary color, depending upon the luminance of the other channels in the region.

A better test would display a test pattern in different colors, but matching luminosity. The trouble with testing this on your computer is that your display must be calibrated. On a properly calibrated display, the display of RGB[0,255,0] and RGB[0,0,255] should have identical luminance values. Very few people have calibrated displays, and even if you do, the chances that your display is accurate throughout the color gamut for a given luminance value is even less.

[jemfinch]

> On a properly calibrated display, the display of RGB[0,255,0] and RGB[0,0,255] should have identical luminance values.

It does, and your eyes still suck at blue.

Why do you fight so vehemently against the scientific fact that your eyes have fewer blue receptors?

[bradleyland]

I'm not arguing against for or against that fact. I'm arguing that these "testing" methodologies are flawed. I'm, apparently, doing a very poor job of expressing the distinction.

Let me state in as clearly as I can:

* A good test would ensure that the luminance values for all colors matched exactly throughout the test image.

* Said test would need to be displayed using a device that is calibrated to ensure displayed luminance matches encoded luminance.

* A test that pulls color data from a source image with mixed luminance values in each channel is flawed.

* This statement makes absolutely no claim as to the human ability perceive any of these colors.

[confuzatron]

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)

[bradleyland]

It's relevant because the testing method is flawed. Illustrating a fact using a flawed example/method is bad science.

[confuzatron]

Sorry, no. You've really missed the point I'm afraid.

A little bit of knowledge, as they say...

[ramidarigaz]

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

[ivank]

If you have an LCD screen with a normal RGBRGB pixel layout, you really can't expect problems. Then again, you can always use a magnifying glass.

[confuzatron]

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?