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A visualization of the RGB space covered by named colors

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Re: A visualization of the RGB space covered by named colors

#71

Post by mrgaro »

meodai wrote: post #66
jl6 wrote: post #38

Wait, does this not use the colornames.org dataset?

No it does not colornames.org emerged after my color name list.

I'm curious to understand the need to have names for such many different colors and I'd love to hear your take! A naive reasoning would say that names are useful if at least two different persons know the meaning for a name and thus it will help communication.

Now I'm not sure how many colors are there in that list, but it feels like there are too many to be practically useful. How do you see this?

Re: A visualization of the RGB space covered by named colors

#72

Post by adrian_b »

virtualritz wrote: post #48

RGB is a color model[1], not a color space[2]. Note that the headline gets this wrong but the page linked to gets this right. sRGB or Rec2020 or ACEScg etc. are color spaces with known primaries and a known whitepoint. This is not nit-picky. Almost everyone doing CGI for the first time w/o reading up on some theory beforehand gets this wrong (because of gamma and then premultiplication, usually in that order). Then t…

While you are right, sometimes "RGB" is used as an abbreviation for some color space that is understood from the context, e.g. the CIE 1931 RGB color space (from which the CIE XYZ color space has been derived) or the RGB decoded correspondent of some TV color space, e.g. NTSC, PAL or SECAM.

Re: A visualization of the RGB space covered by named colors

#73

Post by IgorPartola »

dahart wrote: post #59
subb wrote: post #57

Earlier quoted context omitted.

Except color is a construction of your eye-brain derived from stimuli, surround, memories, etc. It's definitely not something you can plug into a three-value model. Those are good stimuli encoding space, however. The distinction between brain-color and physical-color is what screws everyone up.

> It's definitely not something you can plug into a three-value model. What do you mean? And what is screwed up? We use 3 dimensions because most of us are trichromats, and because (un-coincidentally) most digital display devices have 3 primaries. The three-value models definitely are sufficient for many color tasks & goals. Three-value models work so well that outside of science and graphics research it’s hard to fi…

I had experimented with some photo printing services and came across one professional level service that offered pigment inkjet printing (vs much more common dye inkjet printing). Their printers had 12 colors of ink vs the traditional 4. I did some test photos and visually they looked stunning.

Re: A visualization of the RGB space covered by named colors

#74

Post by IgorPartola »

chime wrote: post #11
Eric_WVGG wrote: post #5

I use a similar app called Name That Color — https://chir.ag/projects/name-that-color/#6195ED I like sharing descriptive names with designers instead of naming everything "light blue" "dark blue" "not quite as light but still not dark blue" etc. This new thing is tons of fun but seems a bit less practically useful.

You just reminded me that my app turned 18 a few months ago. Another dev, Daniel Flück, extended the app to help color blind users: https://www.color-blindness.com/color-name-hue/

I am curious why in your example you compare indigo to violet and purple since purple has a major red component while indigo and violet are on the complete opposite end of the visible color spectrum and are single wavelength colors.

Re: A visualization of the RGB space covered by named colors

#75

Post by virtualritz »

adrian_b wrote: post #72
virtualritz wrote: post #48

RGB is a color model[1], not a color space[2]. Note that the headline gets this wrong but the page linked to gets this right. sRGB or Rec2020 or ACEScg etc. are color spaces with known primaries and a known whitepoint. This is not nit-picky. Almost everyone doing CGI for the first time w/o reading up on some theory beforehand gets this wrong (because of gamma and then premultiplication, usually in that order). Then t…

While you are right, sometimes "RGB" is used as an abbreviation for some color space that is understood from the context, e.g. the CIE 1931 RGB color space (from which the CIE XYZ color space has been derived) or the RGB decoded correspondent of some TV color space, e.g. NTSC, PAL or SECAM.

I would really like to understand where that "sometimes" is, nowadays.

RGB just means that color is expressed as a triplet of specific wavelengths. But what is red? And what does red = 1.0 mean w/o context (aka primaries & whitepoint)? What about HDR? What does green = 2.0 convey? Etc.

For context, I worked in VFX production from the 90's to the early 2010's. About 25 years.

And in commercially available VFX-related software, until the early 2000's, mostly, RGB meant non-linear sRGB, unfortunately (or actually: "whatever" would be more true).

And it shows. We have VGX composed in non-linear color space with blown-out, oversaturated colors in highlights, fringes from resulting alpha blending errors, etc. A good compositor can compensate for some of these issues but only so far. If the maths are wrong, stuff will look shitty to some extend. Or as people in VFX say: "I have comments."

After that, SIGGRAPH courses etc. ensured people were developing an understanding on how much this matters.

And after that we had color spaces and learned to do everything in linear. And never looked back.

Games, as always, caught up a decade after. But they, too, did, eventually.

Re: A visualization of the RGB space covered by named colors

#76

Post by wongarsu »

IgorPartola wrote: post #73
dahart wrote: post #59

Earlier quoted context omitted.

> It's definitely not something you can plug into a three-value model. What do you mean? And what is screwed up? We use 3 dimensions because most of us are trichromats, and because (un-coincidentally) most digital display devices have 3 primaries. The three-value models definitely are sufficient for many color tasks & goals. Three-value models work so well that outside of science and graphics research it’s hard to fi…

I had experimented with some photo printing services and came across one professional level service that offered pigment inkjet printing (vs much more common dye inkjet printing). Their printers had 12 colors of ink vs the traditional 4. I did some test photos and visually they looked stunning.

"You only need three colors" is a bit of a cheat, because it doesn't really work out in reality. You can use three colors to get a good color gamut (as your screen is doing right now), but to represent close to every color we can see you would need to choose a red and blue close to the edge of what we can perceive, which would make it very dim. And because human vision is weird you would need some negative red as well, which doesn't really exist.

Printing instead uses colors that are in the range we can perceive well, and whenever you want a color that is beyond what a combination of the chosen CMYK tones can represent you just add more colors to widen your gamut. Also printed media arguably prints more information than just color (e.g. "metal" colors with different reflectivity, or "neon" colors that convert UV to visible light to appear unnaturally bright)

Re: A visualization of the RGB space covered by named colors

#77

Post by jcattle »

I've recently used two decades of satellite data to compute average colors for land-cover types (like average forest color or average water color).

If you want to extend your color naming game by being able to say: This looks like Afghanistan-Water, or this looks like Ecuador-Forest

Page is here: https://landshade.com

Re: A visualization of the RGB space covered by named colors

#78

Post by IgorPartola »

wongarsu wrote: post #76
IgorPartola wrote: post #73

Earlier quoted context omitted.

I had experimented with some photo printing services and came across one professional level service that offered pigment inkjet printing (vs much more common dye inkjet printing). Their printers had 12 colors of ink vs the traditional 4. I did some test photos and visually they looked stunning.

"You only need three colors" is a bit of a cheat, because it doesn't really work out in reality. You can use three colors to get a good color gamut (as your screen is doing right now), but to represent close to every color we can see you would need to choose a red and blue close to the edge of what we can perceive, which would make it very dim. And because human vision is weird you would need some negative red as wel…

Which is interesting because I am printing digital photos which I edit on an RGB screen.

Re: A visualization of the RGB space covered by named colors

#79

Post by utopiah »

Neat, inspired me to make an immersive version (in WebXR) limited to named colors in HTML (140) so here is a 18s video https://video.benetou.fr/w/rugsEB2sSbqgixNm2QjumH

11 lines of JavaScript thanks to AFrame, threejs and some of my own tinkering :

  fetch('colors.json').then( res => res.json() ).then( colors => {
  colors.map( c => {
  let boxEl = document.createElement("a-box")
  boxEl.id = 'color_'+c.name
  let [r,g,b] = c.rgb.replace('RGB(','').replace(')','').split(',').map( n => Number(n)/100 )
  let pos = `${1-r} ${0.5+g} ${-0.5-b}`
  boxEl.setAttribute("position", pos)
  boxEl.initialPosition = pos
  boxEl.setAttribute("scale", ".1 .1 .1")
  boxEl.setAttribute("color", c.name)
  boxEl.setAttribute("target", "")
  boxEl.setAttribute("onpicked", "setFeedbackHUD('color'+selectedElements.at(-1).element.getAttribute('color'))" )
  boxEl.setAttribute("onreleased", "let el = selectedElements.at(-1).element; el.setAttribute('position',el.initialPosition)" )
  AFRAME.scenes[0].appendChild(boxEl)
  }) // end of fetch()

Re: A visualization of the RGB space covered by named colors

#80

Post by subb »

dahart wrote: post #59
subb wrote: post #57

Earlier quoted context omitted.

Except color is a construction of your eye-brain derived from stimuli, surround, memories, etc. It's definitely not something you can plug into a three-value model. Those are good stimuli encoding space, however. The distinction between brain-color and physical-color is what screws everyone up.

> It's definitely not something you can plug into a three-value model. What do you mean? And what is screwed up? We use 3 dimensions because most of us are trichromats, and because (un-coincidentally) most digital display devices have 3 primaries. The three-value models definitely are sufficient for many color tasks & goals. Three-value models work so well that outside of science and graphics research it’s hard to fi…

They are very useful to encode stimuli, but stimuli is "not yet" color. When you have an image that is not just a patch of RGB value, a lot of things will influence what color you will compute based on the exact same RGB.

Akiyoshi's color constancy demonstrations are good examples of this. The RGB model (and any three-values "perceptual" model) fails to predict the perceived color here. You are seeing different colors but the RGB values are the same.

https://www.psy.ritsumei.ac.jp/akitaoka/marie-eyecolorconsta...

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