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47 votes

Why do we use RGB instead of wavelengths to represent colours?

The goal of the imaging engineer has always been to capture with the camera a faithful image of the outside world and present that image in such a way that the observer sees true to life picture. This ...
Alan Marcus's user avatar
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36 votes

Why do we use RGB instead of wavelengths to represent colours?

You said, this is the information that is captured at first by digital cameras. That is not correct. By themselves, sensors on most digital cameras respond to a broad band of frequencies of light, ...
scottbb's user avatar
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26 votes
Accepted

Why is CMYK more efficient/beneficial than RGB for performing printing operation on white paper?

Both photographic film and photographic digital imaging chips are sensitive to the three light primary colors. In other words, both record components of the image i.e. red, green and blue. ...
Alan Marcus's user avatar
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20 votes

Why is CMYK more efficient/beneficial than RGB for performing printing operation on white paper?

Let me debunk one thing: "RGB and CMY are two different color models." They are not, they both form part of one RGB-CMY model. Or probably an RYGCBM model. Ok. That is not entirely true but ...
Rafael's user avatar
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13 votes

Why do we use RGB instead of wavelengths to represent colours?

The reason cameras and displays work in RGB is because our retinas work that way. Since our eyes encode colors with those components (RGB), it is a very convenient system (although certainly not the ...
heltonbiker's user avatar
12 votes
Accepted

Why do we use RGB instead of wavelengths to represent colours?

I think there are some misconceptions in prior answers, so here's what I think is true. Reference: Noboru Ohta and Alan R. Robertson, Colorimetry: Fundamentals and Applications (2005). A light ...
Guest's user avatar
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12 votes

Why do we use RGB instead of wavelengths to represent colours?

An attempt to answer simply: We cannot practically capture enough information to store a complete breakdown, frequency by frequency, of all the different wavelengths of light present, even just ...
thomasrutter's user avatar
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11 votes

Why is CMYK more efficient/beneficial than RGB for performing printing operation on white paper?

There are two sort of separate issues here. One is RGB vs. CMY. The other is why you add the fourth color, instead of just using CMY (and sometimes, you use half a dozen colors or so, not just four). ...
Jerry Coffin's user avatar
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10 votes
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Filter for RGB separation and its effect on the image

The spectral response of color filters on Bayer masked sensors closely mimics the response of the three different types of cones in the human retina. In fact, our eyes have more "overlap" between red ...
Michael C's user avatar
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10 votes

Why is the screen blend mode named 'screen'?

It's called screen because of the analog process it mimics: From Photoshop Blend Modes Explained : As an analogy, imagine the selected layer and each of the underlying layers as being 35mm slides, ...
L. Scott Johnson's user avatar
8 votes

Why do we use RGB instead of wavelengths to represent colours?

There are two interacting reasons. Reason (1) is that the eye (usually) receives multiple wavelengths of light from any given point [so to speak]. White light, for instance, is actually [as a rule]...
Carsogrin's user avatar
6 votes
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Why do color channels from a digital camera respond slightly to lights of other colors?

There are at least two reasons this happens: There are very few pure (single / narrow frequency band) light sources. That is to say, your red light is not strictly confined to the "red" end ...
scottbb's user avatar
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6 votes
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Can all colors be described with RGB?

Have a look at this introduction to color perception and reproduction. It also contains a comparison of CIE, RGB and CMYK gamuts at the bottom, where CIE represents what the eye can do and RGB and ...
Grimaldi's user avatar
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6 votes

Can all colors be described with RGB?

The colors used in a Bayer filter are already centered as closely as possible to the three wavelengths of light to which human eyes are most sensitive. How sensitive each color is relative to the ...
Michael C's user avatar
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6 votes

How to separate the RGB colour space to only N colours?

The general term is color quantization. When this is done on purpose for artistic effect, this is called posterization (hence the name of the filters in Gimp and Photoshop).
xenoid's user avatar
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5 votes

Why is CMYK more efficient/beneficial than RGB for performing printing operation on white paper?

While RGB and CMY may be similar, adding K changes things. In theory, CMYK values of (0.3,0.3,0.3,0) and (0,0,0,0.3) should appear as identical grays, but in practice there may be differences which ...
supercat's user avatar
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5 votes

Is it true that a camera sensor will never receive an RGB value of R 0 G 255 B 0?

Camera sensors are designed to mimic the way the human eye/brain system perceives a portion of the electromagnetic spectrum as light. Our brains create the perception of color when stimulated by ...
Michael C's user avatar
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4 votes
Accepted

Why does Photoshop Curves in 16 bit color depth still use tonal range 0 - 255?

16-bit is only used for internal calculations. What you actually see on your monitor is in 8-bit. Since an 8-bit monitor can only display 256 levels (0-255) and is unable to display the difference ...
Michael C's user avatar
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4 votes

color spaces and monitors

Adobe RGB image in a monitor that only displays sRGB? I'm not sure if here lies a misconception. A monitor does not only displays sRGB or Adobe 1998, they display a percentage of them. If a monitor ...
Rafael's user avatar
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4 votes

Why is CMYK more efficient/beneficial than RGB for performing printing operation on white paper?

The answer is in your question. It is because TLDR RGB is an additive color model CMYK is a subtractive color model You are using the terms additive color model and subtractive color model without ...
slebetman's user avatar
  • 141
3 votes

Why do color channels from a digital camera respond slightly to lights of other colors?

Why do color channels from a digital camera respond slightly to lights of other colors? Because the filters placed in front of the silicon on a Bayer masked filter all allow some of all the ...
Michael C's user avatar
  • 175k
3 votes

How did color spaces get their names?

Perhaps it’s as simple as the positions occupied by the colors on the spectrum.
Alan Marcus's user avatar
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3 votes
Accepted

How did color spaces get their names?

I presume RGB is in that order simply because it is the common spectral order — RoyGBiv, in other words. You will sometimes see BRG or otherwise when a particular computer image format happens to ...
mattdm's user avatar
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3 votes
Accepted

Do CEIL LAB images look really the same on all monitors?

No. CIELAB images are just as subject to different displays as RGB images. As you note CIELAB is converted to RGB in order to be displayed since displays do not use CIELAB. However, if displays are ...
doug's user avatar
  • 1,217
3 votes

How to color correct using known RGB values of a single pixel?

You aren't going to get it exactly right with a single pixel, though you can certainly get that pixel right and then adjust everything else to be visually pleasing (which is usually close enough). To ...
dgatwood's user avatar
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3 votes

Why do we use RGB instead of wavelengths to represent colours?

The short answer: Because wavelength is a single value, and the entire range of colors we can perceive is not representable by a single value, any more than the dimensions of a rectangular solid can ...
Jamie Hanrahan's user avatar
3 votes

Why do we use RGB instead of wavelengths to represent colours?

tl;dr: It is way much easier to detect light on three broad parts of the spectra than analyse the frequency accurately. Also, the simpler detector means it can be smaller. And third reason: the RGB ...
Crowley's user avatar
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3 votes

RGB adjustment for monitor RGB difference

You don't. Neither is from a colour-managed system. In fact those numbers are so far apart from each other no-one would know whether you actually wanted a greenish grey or a slate blue. Without a ...
Tetsujin's user avatar
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2 votes

Difference between a "camera at three broad spectral bands" (sic.) and a standard RGB camera?

It does not seem to be substantially different from standard CMOS sensor other than the fact that most Illunis cameras seem to be based on CCD rather than CMOS chips. The three color bands centered on ...
Michael C's user avatar
  • 175k
2 votes

Filter for RGB separation and its effect on the image

The color filter is supposed to mimic our eyes perception of color, it does so imperfectly, but usually well enough. The way we understand color perception is based on opponent process theory. For ...
Chris Novak's user avatar
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