5 ms·

All the colors are false, it’s imaging inferred.

by jakear 4y ago

z9znz 4y ago
Politely suggesting that false has some negative connotations, perhaps "artificial" would be a better word... or even illustrative or representational.
- jefftk 4y ago
  "False" is the traditional word here: https://en.wikipedia.org/wiki/False_color https://en.wikipedia.org/wiki/False_color
  - z9znz 4y ago
    Fair enough. Then it's really a matter of intended audience. It is a correct technical term for the color-domain educated audience. Could be that I'm one of the few outside that audience, but probably not :). The wikipedia article does note that pseudo-color is an alternative, and that carries less generally negative connotation. This is all nitpicking anyway, but thanks for the bit of education! [added - although now I can pick at the definition of "true color", since it is based on the idea of how a color would appaer to a human viewer. We know pretty well that there's quite a variance of perception of color amongst humans, so there arguably is no "true color". There's just X% of people see this color. :) ]
  - lapetitejort 4y ago
    For a similar term that can confuse outside audiences, see: https://en.wikipedia.org/wiki/Fictitious_force https://en.wikipedia.org/wiki/Fictitious_force
    - z9znz 4y ago
      Interesting. Perhaps it's like most other things in life. In hindsight, we might have done it differently. In this case, there are probably better, more descriptive (and less confusing) adjectives than "fictitious" which would succinctly describe a non-existent but perceived (or imagined) force. Even so, I never visualized something pushing me back into the seat. I always visualized the seat pressing against me. After all, I didn't feel sensations on the front of my body when accelerating. The sensations are the same as if someone has come from behind and starting pushing you.
      - jakear 4y ago
        Removing yourself from the equation makes it easier to see: imagine a ball on a string in a car. Something happens and the ball moves forward relative to you. It’s not hard to see how you might assume a force pushed the ball forward.
TremendousJudge 4y ago
But aren't the percieved colors redshifted? Aren't these "false color" images just blueshifting the colors back to a visible light image, which is how they would look if they were moving at the same relative speed as us?
- jakear 4y ago
  Roughly speaking sure, but the color mapping function they used just paints the longest wavelength the telescope can see “red” and the shortest “violet”. No attempt is made to properly “undo” redshifting. I’ve been unable to find any technical reports on the technique, but the gist of it is here: https://www.axios.com/2022/07/17/james-webb-space-telescope-nasa-photos-processing https://www.axios.com/2022/07/17/james-webb-space-telescope-...
  - heavenlyblue 4y ago
    It does seem like the redshift would need to be fixed on a star-by-star basis depending on how far away is the star.
    - falseprofit 4y ago
      I think you mean galaxy-by-galaxy.
- adgjlsfhk1 4y ago
  depends on the observation. Anything in our galaxy or nearby galaxies is actual infra-red light at the source.
  - giantrobot 4y ago
    That is not true. The light reaching us from most objects in our and nearby galaxies is pretty close to the original wavelength emitted. It takes extremely relative velocity to red shift for visible wavelengths to shift to infrared. Most stellar objects emit a whole bunch of wavelengths of light, some emit more IR than visible. Interstellar dust doesn't red shift light due to velocity but because the molecules absorb higher energy photons and re-emit lower energy photons.
ordu 4y ago
This phrase implies that there are some "true colors", but are they? People see colors in weird ways, and it is a bold move to declare them to be the true ways. https://www.science.org/content/blog-post/chemistry-colors-images-and-reality https://www.science.org/content/blog-post/chemistry-colors-i...
- jakear 4y ago
  Monitors output color via modulating three color channels. The modulation can either vaguely correspond to how the original wavelength would activate the three cone varietals in most humans, or can bear absolutely no relation to that. Equating the two is possible, but lazy.
  - ordu 4y ago
    I do not believe that human perception has anything to do with "true" colors. Such a complex system with so many quirks cannot be called the true way to deal with wavelengths. And yes it starts with cones in a retina, which wipe out most of information about a spectrum of a light. Some information got lost completely, some is mixed up, to a point where it is just vaguely represents the source signal. But if it seems to you too vague, then I can come to a point from a different angle: did you hear about tetrachromacy? "A study from 2010 actually suggests that a rare condition known as tetrachromacy exists in up to 12% of women in the world."[1] Don't you think that these women see colors in a "more true" way than other people? I personally think they are. It means, at least, that a more common way of a trichromacy is not the true way to see colors. It gives us not true colors, but some approximation which is very far from reality. You mentioned "most humans" as a reference point, so probably you believe that the truth can be established by a voting. I do not. I know that the objective truth is an unattainable ideal, but I do not believe that the majority of votes would be enough to establish an acceptable approximation to the ideal. It needs something more than that. [1] https://azretina.sites.arizona.edu/index.php/node/852 https://azretina.sites.arizona.edu/index.php/node/852

All the colors are false, it’s imaging inferred.

by jakear 4y ago

All the colors are false, it’s imaging inferred.

Politely suggesting that false has some negative connotations, perhaps "artificial" would be a better word... or even illustrative or representational.

jefftk 4y ago
"False" is the traditional word here: https://en.wikipedia.org/wiki/False_color https://en.wikipedia.org/wiki/False_color
- z9znz 4y ago
  Fair enough. Then it's really a matter of intended audience. It is a correct technical term for the color-domain educated audience. Could be that I'm one of the few outside that audience, but probably not :). The wikipedia article does note that pseudo-color is an alternative, and that carries less generally negative connotation. This is all nitpicking anyway, but thanks for the bit of education! [added - although now I can pick at the definition of "true color", since it is based on the idea of how a color would appaer to a human viewer. We know pretty well that there's quite a variance of perception of color amongst humans, so there arguably is no "true color". There's just X% of people see this color. :) ]
- lapetitejort 4y ago
  For a similar term that can confuse outside audiences, see: https://en.wikipedia.org/wiki/Fictitious_force https://en.wikipedia.org/wiki/Fictitious_force
  - z9znz 4y ago
    Interesting. Perhaps it's like most other things in life. In hindsight, we might have done it differently. In this case, there are probably better, more descriptive (and less confusing) adjectives than "fictitious" which would succinctly describe a non-existent but perceived (or imagined) force. Even so, I never visualized something pushing me back into the seat. I always visualized the seat pressing against me. After all, I didn't feel sensations on the front of my body when accelerating. The sensations are the same as if someone has come from behind and starting pushing you.
    - jakear 4y ago
      Removing yourself from the equation makes it easier to see: imagine a ball on a string in a car. Something happens and the ball moves forward relative to you. It’s not hard to see how you might assume a force pushed the ball forward.

TremendousJudge 4y ago

But aren't the percieved colors redshifted? Aren't these "false color" images just blueshifting the colors back to a visible light image, which is how they would look if they were moving at the same relative speed as us?

jakear 4y ago
Roughly speaking sure, but the color mapping function they used just paints the longest wavelength the telescope can see “red” and the shortest “violet”. No attempt is made to properly “undo” redshifting. I’ve been unable to find any technical reports on the technique, but the gist of it is here: https://www.axios.com/2022/07/17/james-webb-space-telescope-nasa-photos-processing https://www.axios.com/2022/07/17/james-webb-space-telescope-...
- heavenlyblue 4y ago
  It does seem like the redshift would need to be fixed on a star-by-star basis depending on how far away is the star.
  - falseprofit 4y ago
    I think you mean galaxy-by-galaxy.
adgjlsfhk1 4y ago
depends on the observation. Anything in our galaxy or nearby galaxies is actual infra-red light at the source.
- giantrobot 4y ago
  That is not true. The light reaching us from most objects in our and nearby galaxies is pretty close to the original wavelength emitted. It takes extremely relative velocity to red shift for visible wavelengths to shift to infrared. Most stellar objects emit a whole bunch of wavelengths of light, some emit more IR than visible. Interstellar dust doesn't red shift light due to velocity but because the molecules absorb higher energy photons and re-emit lower energy photons.

ordu 4y ago

This phrase implies that there are some "true colors", but are they? People see colors in weird ways, and it is a bold move to declare them to be the true ways. https://www.science.org/content/blog-post/chemistry-colors-images-and-reality https://www.science.org/content/blog-post/chemistry-colors-i...

jakear 4y ago
Monitors output color via modulating three color channels. The modulation can either vaguely correspond to how the original wavelength would activate the three cone varietals in most humans, or can bear absolutely no relation to that. Equating the two is possible, but lazy.
- ordu 4y ago
  I do not believe that human perception has anything to do with "true" colors. Such a complex system with so many quirks cannot be called the true way to deal with wavelengths. And yes it starts with cones in a retina, which wipe out most of information about a spectrum of a light. Some information got lost completely, some is mixed up, to a point where it is just vaguely represents the source signal. But if it seems to you too vague, then I can come to a point from a different angle: did you hear about tetrachromacy? "A study from 2010 actually suggests that a rare condition known as tetrachromacy exists in up to 12% of women in the world."[1] Don't you think that these women see colors in a "more true" way than other people? I personally think they are. It means, at least, that a more common way of a trichromacy is not the true way to see colors. It gives us not true colors, but some approximation which is very far from reality. You mentioned "most humans" as a reference point, so probably you believe that the truth can be established by a voting. I do not. I know that the objective truth is an unattainable ideal, but I do not believe that the majority of votes would be enough to establish an acceptable approximation to the ideal. It needs something more than that. [1] https://azretina.sites.arizona.edu/index.php/node/852 https://azretina.sites.arizona.edu/index.php/node/852