How many color tones do your eyes see?

[bad karma]

I recently read that 12 bit cameras can output 4,000+ color tones, while 14 bit cameras (40D, 5D) can output 16,000+ color tones. Something along those lines (correct me if I am wrong). But how many color tones does the eye itself have a capability of seeing?

[Ook]

From what I heard, we see more or less in 8-bit, in terms of levels of brightness. Our ability to quickly auto-adjust to whatever we're seeing is more important in our visual experience than just being able to detect many different brightness levels, which is essentially what you mean by colour tones.

I consider shooting in 14-bit more useful for processing headroom than displaying accurate information.

[chauncey]

About 10 million.

[cdifoto]

I'm an idealist. That means I see in two tones: black and white. :D

[tzalman]

About 10 million.

10 million discrete colors. Which in an RGB display would be equivalent to 215 tonal levels per channel, close to Ook's answer. (8 bit's 256 levels produce 16 million colors.) Which is why for display purposes 8 bit is perfectly adequate.

[neumanns]

Deeper bit depth is about proccesing lattitude not display. When you start pushing and pulling things you have a lot more flexiblity before they break. For example poserization in the sky ...

[Tee Why]

I'd guess the human eye can see several hundred different colors, maybe a thousand?

[adas]

I certainly see more than 65536 colors. If I switch down my video card to 16bit color depth (65536 colors), I can see posterization in images, and not just slight.

[DStanic]

I certainly see more than 65536 colors. If I switch down my video card to 16bit color depth (65536 colors), I can see posterization in images, and not just slight.

Video cards must be different than cameras- cause I can also tell an obvious difference from 16bit and 32bit, however a camera can shoot at 8bit or 14bit and look fine to me. ???

[adas]

In cameras they say 8bit or 12bit or 14bit per color channnel. So even the cheapest Jpeg only P&S will have 24bit color depth. (8bit in each of the 3 channels: R,G,B)

[DStanic]

In cameras they say 8bit or 12bit or 14bit per color channnel. So even the cheapest Jpeg only P&S will have 24bit color depth. (8bit in each of the 3 channels: R,G,B)

That makes perfect sense now, thanks for clearing that up! :)

[bad karma]

In cameras they say 8bit or 12bit or 14bit per color channnel. So even the cheapest Jpeg only P&S will have 24bit color depth. (8bit in each of the 3 channels: R,G,B)
Very well explained, makes better sense! Thank you!

[nphsbuckeye]

All of them.

[Tee Why]

Looking around online it seems like a ball park figure of 7 million or so comes up a lot.
http://www.colormatters.com/optics.html

I suspect that this is a theoretical number as I doubt there has actually been a test where a person identified 7 million different colors.

According to this poster testing the 12 vs 14 bit RAW images, he doesn't see any difference and with a 12bit image using sRGB you can get up to 16million colors or more? (I skimmed through the math).
http://www.photomatter.com/Reviews/NikonD300d.html

Here is another site comparing Nikon's 12 vs 14 bit shots at 300% crops.
http://www.earthboundlight.com/phototips/14-bit-raw-12-bit-part-two.html

I've heard that the Nikon d300 folks at dpreview forum have been going over the 12 vs 14 bit discussion as that camera can shoot in both, unlike Canon's, and hear that they don't see any practical, real world difference.

[AndreaBFS]

I'm an idealist. That means I see in two tones: black and white. :D

Heh. Me too. That's always so convenient when we agree with each other. But watch out when we don't. ;)

[adas]

Looking around online it seems like a ball park figure of 7 million or so comes up a lot.
http://www.colormatters.com/optics.html

I suspect that this is a theoretical number as I doubt there has actually been a test where a person identified 7 million different colors.

I guess the tests were probably on how the eye can distinguish between two shades of adjacent colors taken at various bit depths, so it probably came out a density of about 7million.
But more important is the color gamut perceived, which is so much wider for the eye than even the best cameras with tens of millions or even billions of colors.

[Mark_48]

Red, Green, and Blue. Any other color tone is simply the combining of these primary colors to different degrees. Black is not a color tone, but an absence of color. White is an equal combination of Red, Green, and Blue. The range of combination tones between Black and White would probably be close to infinite. The perception of a color tone may vary from person to person due to the eyes variance in sensitivity to the primary colors or other factors related to health or age.

http://www.glenbrook.k12.il.us/gbssci/Phys/Class/light/u12l2b.html

[20droger]

10 million discrete colors. Which in an RGB display would be equivalent to 215 tonal levels per channel, close to Ook's answer. (8 bit's 256 levels produce 16 million colors.) Which is why for display purposes 8 bit is perfectly adequate.
Could you name them, please?

Men see 16 colors. Peach is a fruit. Avocado is a fruit. Plum is a fruit. Mauve is a God only knows what!

[Mark_48]

Could you name them, please?

Men see 16 colors. Peach is a fruit. Avocado is a fruit. Plum is a fruit. Mauve is a God only knows what!

These are are I need to know...:)

http://www.crayola.com/colorcensus/history/current_120_colors.cfm

.

[Wilt]

Here's an interesting conundrum...if people can see only 7-10 million colors, why has HP developed a monitor, the HP DreamColor monitor, a 30 bit panel intended to display one billion colors when paired with a 10 bit graphics card, when most high-end monitors — and graphics cards - max out at 24 bit, or 16.7 million colors??? When CRTs were king, there were a few very high end units capable of 24 million colors. So everything apparently exceeds what the eye can perceive, so why bother?!

[Mark_48]

Here's an interesting conundrum...if people can see only 7-10 million colors, why has HP developed a monitor, the HP DreamColor monitor, a 30 bit panel intended to display one billion colors when paired with a 10 bit graphics card, when most high-end monitors — and graphics cards - max out at 24 bit, or 16.7 million colors??? When CRTs were king, there were a few very high end units capable of 24 million colors. So everything apparently exceeds what the eye can perceive, so why bother?!

Marketing gimmick that will sell a monitor at a high price (?)

[Wilt]

I just found an article speculating about one woman's ability to see in more colors than the typical person...

"It may be impossible for us trichromats to imagine what a four-color world would look like. But mathematics alone suggests the difference would be astounding, said Jay Neitz, a renowned color vision researcher at the Medical College of Wisconsin.

Each of the three standard color-detecting cones in the retina -- blue, green and red -- can pick up about 100 different gradations of color, Dr. Neitz estimated. But the brain can combine those variations exponentially, he said, so that the average person can distinguish about 1 million different hues."

A tetrachromat is a woman who can see four distinct ranges of color, instead of the three that most of us live with.

The article continues...
"That's because the genes for the pigments in green and red cones lie on the X chromosome, and only women have two X chromosomes, creating the opportunity for one type of red cone to be activated on one X chromosome and the other type of red cone on the other one. In a few cases, women may have two distinct green cones on either X chromosome.

"But it's unlikely, Dr. Neitz said, that all of the women with four types of color cones will have the potential for superior color vision, because for many, their two red cones will be so close to each other in the wavelengths they detect that they won't see things much differently than a three-color person does.

"He estimated that 2 percent to 3 percent of the world's women may have the kind of fourth cone that lies smack between the standard red and green cones, which could give them a colossal range."

And the article goes on to state...

"About 8 percent of the world's men have color deficiency, which is the term vision researchers prefer to color blindness.

"Most of them inherit two red or two green cones along with the standard blue cone, making it impossible for them to distinguish between red and green peppers, or tell how well-done a steak is, or pick out matching clothes."

So now we have an expert saying 'one million' and other articles stating between 7-10 million, and speculation about 'tetrachromats' with 100 million. So the HP monitor seems like definite overkill, at 1 billion!

[bad karma]

When the computer setting say either 16 or 32 bit, do they refer to each color channel or just the entire resolution set?

[Wilt]

When the computer setting say either 16 or 32 bit, do they refer to each color channel or just the entire resolution set?

Perhaps none of the above!

16-bit vs. 32-bit can refer simply to the processing space of the processor (how much virtual memory) -- for computing geeks

16-bit vs. 32-bit can also refer to the number of bits allocated in total to pixel rendition of color (R-G-B, 8 bits each typical, totalling 24 bits) and grayscale (12-bit or 14-bit) vs what the pixel is stored in in JPG vs. TIFF format files -- for photographic geeks

[adas]

When the computer setting say either 16 or 32 bit, do they refer to each color channel or just the entire resolution set?

It's the entire resolution set.

16bit = 5bit RED + 6bit GREEN + 5bit BLUE (now obsolete)
32bit = 8bit RED + 8bit GREEN + 8bit BLUE + 8bit ALPHA

The ALPHA channel stores the transparency level of the pixel and it's used when displaying multiple layers and surfaces by the video card.

[Madweasel]

Red, Green, and Blue. Any other color tone is simply the combining of these primary colors to different degrees. Black is not a color tone, but an absence of color. White is an equal combination of Red, Green, and Blue. The range of combination tones between Black and White would probably be close to infinite. The perception of a color tone may vary from person to person due to the eyes variance in sensitivity to the primary colors or other factors related to health or age.

http://www.glenbrook.k12.il.us/gbssci/Phys/Class/light/u12l2b.html
The range of colours you can produce in this way is called the gamut. It depends on exactly what colour those 'primaries' are. If you plot them in colour space (CIE is commonly used), the gamut is all colours within the triangle described by the position of those primaries. However the whole range of 'possible' colours will always have some that are outside this gamut, in other words you can't create 'all' colours by combining red, green and blue, no matter what shades they are.

As human vision also works with three colour sensors, there are also colours that can be measured to be different but which we cannot distinguish, so the best solution is to choose primaries that best match the three colour receptors in the human eye.

It all gets more complicated when you also factor in the light source. Then, under a given light source two colours may appear the same, but under a different light source they may be distinguished (due to differently-shaped spectral reflectance curves). This is called metamerism.

Sorry, I got carried away - I used to work in camouflage (no jokes please - I've heard them all!).

[adas]

It depends on exactly what colour those 'primaries' are. If you plot them in colour space (CIE is commonly used), the gamut is all colours within the triangle described by the position of those primaries. However the whole range of 'possible' colours will always have some that are outside this gamut, in other words you can't create 'all' colours by combining red, green and blue, no matter what shades they are.


1) I thought primaries are only one kind, and strictly defined by CIE.

2) But since the human eye has RGB receptors, those colors you can't create by combining RGB shades are invisible for humans, therefore unimportant. Namely infrared, ultraviolet, alpha, beta, gamma etc.