explain xkcd - User contributions [en]

1882: Color Models

2017-08-28T23:11:17Z

Hakr14:

{{comic
| number = 1882
| date = August 28, 2017
| title = Color Models
| image = color_models.png
| titletext = What if what *I* see as blue, *you* see as a slightly different blue because you're using Chrome instead of Firefox and despite a decade of messing with profiles we STILL can't get this right somehow.
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

Randall is describing how his level of understanding of colors has changed by age. The chart starts with two tracks of understanding color.

In grade school he learned about the primary colors, and the very simple model of colors, as shown in the left track. Mixing of color solids, as in painting (or finger painting being probably the earliest exposure to color mixing), is intuitive for a child. The process is subtractive, and the more colors you mix the darker and closer to black you get. Color is seen by the eyes when light bounces off the solid colors and becomes light of different wavelengths that the eye can then see. However at this level, things just "look" like different colors without understanding light's role.

The right track is mixing of color light, as in prisms and light waves, where mixing colors is additive and the more you mix the lighter and closer to white you get. But this is without a real understanding of light bouncing off surfaces, and is limited to an understanding of different colors of light and how they mix. The first exposure in grade school is usually by shining white light through a prism to separate it into the different visible colors.

The [http://en.wikipedia.org/wiki/Opponent_process opponent color model] connects these two models, by explaining how different wavelengths of light are absorbed by different rods and cones in the eyes.

The "complex multidimensional gamut" mentions two more models: [http://en.wikipedia.org/wiki/CIE_1931_color_space CIE 1931] and [http://en.wikipedia.org/wiki/Lab_color_space L*a*b*]. These are more detailed models based on the opponent color model, which precisely define how a particular color maps to the different channels that our eyes see.

However, understanding how the eye sees color ''still'' isn't enough, because not every device can display all the colors your eye can see. Your laptop might have a different [http://en.wikipedia.org/wiki/Gamut color gamut] than your phone, and if you printed the page out, you might see yet another color. To handle this issue, web browsers use "color profiles", so that an image can be tagged with the color space it uses and the browser can handle it appropriately. Unfortunately, browsers do this inconsistently and not very well. The title text expands on this joke, implying that the reason for the "unknowable" answer above is that everyone's browser shows colors slightly differently.

The "hyperdimensional four-sided quantum Klein manifold" is probably a joke. A "Klein manifold" is a Klein bottle. Randall is here projecting a "abstract multidimensional gamut" onto an even more complicated surface, presumably in order to eliminate the errors in color rendering caused by previous attempts to eliminate the errors in color rendering. The Klein bottle has to be projected into 4-D space for this to work, as it would otherwise intersect with itself. This seems to actually be "a thing" in that you could do it, but not a "thing" in that nobody has done it. A "Klein Quantum" is a kind of bicycle.

Eventually it appears Randall has given up, hoping he won't have to deal with the difficulty in describing and understanding the concept of colors.

The title text indicates that, despite the complexity and thoroughness of color models, the most common software on Earth can't get it right.

==Transcript==
{{incomplete transcript|Needs arrows like a flowchart}}

:Evolution of my understanding of color over time:

:Grade school
:|
:| "Color" is...
:| ...three primary colors mixed together
:| ...a rainbow, and each color is a wavelength
:| ...unknowable ("maybe what ''I'' see as blue, ''you'' see as...")
:| ...three-ish primary colors mixed together (RGB/RYB/CMYK)
:| ...a mix of infinite wavelengths filtered through three eye pigments
:| [something about the opponent color model]
:| ...an abstract multidimensional gamut (CIE 1931, L*a*b*, etc)
:| ...an abstract multidimensional gamut filtered through inconsistently-implemented device color profiles
:| ...a hyperdimensional four-sided quantum Klein manifold? Is that a thing?
:| ...hopefully somebody else's problem.
:|
:Now

{{comic discussion}}

Talk:1882: Color Models

2017-08-28T23:09:39Z

Hakr14:

For those who want to know a bit more about color, [https://www.handprint.com/LS/CVS/color.html this site] is a good start. [[User:Zmatt|Zmatt]] ([[User talk:Zmatt|talk]]) 15:08, 28 August 2017 (UTC)

This comic shows the trend of having a simple and satisfactory explanation for something, and the exasperation with repeatedly realizing the inadequacy of the explanation, making revisions, and having a more complex yet still inadequate model.

As Randall began his schooling, he learned that mixing the primary colours of pigment (red, blue, and yellow) together he could create almost any colour, so colour must be a combination of those 3 colours.

He also learned about rainbows, and that the colours in the rainbow were just different wavelengths of light. Somehow these different wavelengths created unique colours.

As Randall got older, philosophy and a discussion on perception came into play, and Randall came to the realization that his experiences are analogous to but not necessarily the same as his peers.

As he got older, Randall learned about colour spaces as used in pigments, light, and printing, possibly from computer science (Red, Green, Blue; Red, Yellow, Blue; Cyan, Magenta, Yellow, Key) as well as the physics of electromagnetic rays and the biology of vision, understanding that visible light is a small portion of the electromagnetic spectrum - one crudely interpreted by the 3 types of cones in our eyeballs.

Randall then learned about the opponent process model, wherein the signal from cones are not interpreted individually, but in difference to one another. "Responses to one color of an opponent channel are antagonistic to those to the other color. That is, opposite opponent colors are never perceived together – there is no "greenish red" or "yellowish blue"." (from wikipedia)

After that, Randall comes to understand the modeling of colour spaces and the design and limits of human visual perception - despite only having three cones, color space cannot be made into a triangle and still cover the gamut of human colour experience.

Klein manifolds are beyond me, you'll have to fill in something about that.

Eventually, the modeling becomes so complex (and yet still unsatisfactory) that Randall hopes it becomes someone else's problem. [[Special:Contributions/108.162.238.5|108.162.238.5]] 15:50, 28 August 2017 (UTC)MagnusVortex

I'm familiar with klein manifolds, they're peculiar 4D dimensional topological objects related to mobius strips. I have no Idea how they might relate to color, and doing a search for "a hyperdimensional four-sided quantum Klein manifold" returned pictures of bicycles...

It might be good to point out in the explaination that he progresses from a dual nature of color (light, and paint) at the beginning and then trends to a unified explaination of color. [[Special:Contributions/172.68.142.179|172.68.142.179]] 18:27, 28 August 2017 (UTC) Sam

: Yes those are great looking bikes and are called Klein Quantum racing bikes... so Google did its job of keyword matching. [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 20:40, 28 August 2017 (UTC)

;The beauty of explainxkcd
The explanation of this comment is a great example of why this site is delightful — and nigh-invaluable! Thanks, regulars, for doing the work to help us understand all this.{{unsigned ip|108.162.246.101}}

----

Text explanation

I think the explanation of the text is missing an important point. It starts like it's about the philosophal question of "the same color for everybody", but ends with a very mundane explanation, which I think quite funny.

[[Special:Contributions/141.101.69.9|141.101.69.9]] 21:18, 28 August 2017 (UTC) Loïc

----

"As the 4th dimension is time, the color space would probably change all the time."

...no. No. I'm removing that. Just... no.

[[User:Hakr14|Hakr14]] ([[User talk:Hakr14|talk]]) 23:03, 28 August 2017 (UTC)

Talk:1882: Color Models

2017-08-28T23:03:45Z

Hakr14:

For those who want to know a bit more about color, [https://www.handprint.com/LS/CVS/color.html this site] is a good start. [[User:Zmatt|Zmatt]] ([[User talk:Zmatt|talk]]) 15:08, 28 August 2017 (UTC)

This comic shows the trend of having a simple and satisfactory explanation for something, and the exasperation with repeatedly realizing the inadequacy of the explanation, making revisions, and having a more complex yet still inadequate model.

As Randall began his schooling, he learned that mixing the primary colours of pigment (red, blue, and yellow) together he could create almost any colour, so colour must be a combination of those 3 colours.

He also learned about rainbows, and that the colours in the rainbow were just different wavelengths of light. Somehow these different wavelengths created unique colours.

As Randall got older, philosophy and a discussion on perception came into play, and Randall came to the realization that his experiences are analogous to but not necessarily the same as his peers.

As he got older, Randall learned about colour spaces as used in pigments, light, and printing, possibly from computer science (Red, Green, Blue; Red, Yellow, Blue; Cyan, Magenta, Yellow, Key) as well as the physics of electromagnetic rays and the biology of vision, understanding that visible light is a small portion of the electromagnetic spectrum - one crudely interpreted by the 3 types of cones in our eyeballs.

Randall then learned about the opponent process model, wherein the signal from cones are not interpreted individually, but in difference to one another. "Responses to one color of an opponent channel are antagonistic to those to the other color. That is, opposite opponent colors are never perceived together – there is no "greenish red" or "yellowish blue"." (from wikipedia)

After that, Randall comes to understand the modeling of colour spaces and the design and limits of human visual perception - despite only having three cones, color space cannot be made into a triangle and still cover the gamut of human colour experience.

Klein manifolds are beyond me, you'll have to fill in something about that.

Eventually, the modeling becomes so complex (and yet still unsatisfactory) that Randall hopes it becomes someone else's problem. [[Special:Contributions/108.162.238.5|108.162.238.5]] 15:50, 28 August 2017 (UTC)MagnusVortex

I'm familiar with klein manifolds, they're peculiar 4D dimensional topological objects related to mobius strips. I have no Idea how they might relate to color, and doing a search for "a hyperdimensional four-sided quantum Klein manifold" returned pictures of bicycles...

It might be good to point out in the explaination that he progresses from a dual nature of color (light, and paint) at the beginning and then trends to a unified explaination of color. [[Special:Contributions/172.68.142.179|172.68.142.179]] 18:27, 28 August 2017 (UTC) Sam

: Yes those are great looking bikes and are called Klein Quantum racing bikes... so Google did its job of keyword matching. [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 20:40, 28 August 2017 (UTC)

;The beauty of explainxkcd
The explanation of this comment is a great example of why this site is delightful — and nigh-invaluable! Thanks, regulars, for doing the work to help us understand all this.{{unsigned ip|108.162.246.101}}

----

Text explanation

I think the explanation of the text is missing an important point. It starts like it's about the philosophal question of "the same color for everybody", but ends with a very mundane explanation, which I think quite funny.

[[Special:Contributions/141.101.69.9|141.101.69.9]] 21:18, 28 August 2017 (UTC) Loïc

"As the 4th dimension is time, the color space would probably change all the time."

...no. No. I'm removing that. Just... no.

[[User:Hakr14|Hakr14]] ([[User talk:Hakr14|talk]]) 23:03, 28 August 2017 (UTC)

User:Hakr14

2015-09-30T17:42:08Z

Hakr14: Created page with "I'm just making this so my name isn't red."

I'm just making this so my name isn't red.

1446: Landing

2015-09-29T17:51:45Z

Hakr14: Why wan't this already done?

{{comic
| number = 1446
| date = November 12, 2014
| title = Landing
| image = landingAnimated.gif
| titletext = [LIVE]
}}
Frames of the comic began appearing at midnight ({{w|Eastern Time Zone|EST}}) on November 12, 2014 and updated every five minutes. Together, the images form a {{w|flip book}} which is shown here above. You can find the individual images by clicking on the latest image of the comic on xkcd (go to that by clicking the date above or find it directly at [http://xkcd1446.org xkcd1446.org]).

==Explanation==
This comic changed over time during 12 hours and 15 minutes starting at 0:00 EST (when the comic normally is released) posting 143 pictures that tracked the progress of the {{w|Philae (spacecraft)|Philae}} lander separating from the {{w|European Space Agency}}'s {{w|Rosetta (spacecraft)|Rosetta}} probe to land on comet {{w|67P/Churyumov–Gerasimenko}}. More info can be found here: [http://rosetta.esa.int rosetta.esa.int].

The comic presents the imagined anthropomorphic "thoughts" of the Rosetta spacecraft and the Philae lander (and occasionally other parties) during the hours approaching separation from each other, approach to the comet and finally the apparently successful landing on the comet.

Beginning at [[Media:???65.png|11:05]], the comic includes a '''"Status Report"''' in the lower right corner which summarizes the status of various interested parties and accomplishments, beginning with "Rosetta", "Philae lander", "Mission Control", "Comet 67P", and "Have we landed on a comet?". As events occur in the comic, more status summaries are added to keep track of the changes to the situation and the supposed emotions behind them.

In many pictures a whale can be seen on the surface of the comet - often marked with a "?" as are almost all other parts of the unknown surface at this time. There is also drawn a [[Cueball]] on the surface also marked with a "?" Both are then at some point marked with a ''probably not'' - starting from [[Media:???83.png|12:35]]. The whales are also mentioned in the "Status Report" where they for instance may be listed as "calm" or "(probably) not in space". At [[Media:???122.png|16:00]] the when the entire Earth goes ''AAAAAAAAAAA'' the whales are listed as saying this as well (along with Mission control and U.S. scientists). From this moment "Dolphins and fish" are also mentioned in the report. They are asking if it is the whales that scream. The reference to whales comes from the fact that Philae brought along two harpoons that should have been used to anchor it to the comet. On Earth, harpoons have mainly been used to hunt whales; Randall previously brought up that comparison in [[1402: Harpoons]], suggesting that Philae was programmed to believe it was sent to kill the comet. It is Philae that "dreams" about whales on the surface of the comet which can be seen in the picture for [[Media:???93.png|13:25]] and in the status report.

Some {{w|Douglas Adams}} fans believe these whales and dolphins are references to ''{{w|The Hitchhiker's Guide to the Galaxy}}'' and ''{{w|So Long, and Thanks for All the Fish}}.'' Whales in space have been appearing in fiction and art since the 1960s. However, with the above mentioned reasons for whales, dolphins and fish, this seems less and less likely.

Shortly after release from Rosetta ([[Media:???56.png|10:15]]), Philae calls out 'Spaaaaaaaaaace'; this mimics the {{w|Portal 2}} 'Space core' who, on finally reaching space in the last scenes, gives the same elated cry.

US Scientists presumably wake up at 7:40 EST ([[Media:???96.png|13:40]] UTC) and in the report they now says "Bluuurghhh. What time is it?" to indicate their tiredness. This does not change until 10:25 EST ([[Media:???115.png|15:25]] UTC) so they are slow to wake (2 hours 45 minutes). At this point, they becomes anxious as there are only 10 minutes to landing. This last until there is 15 minutes until news of landing (a reference to the 28 minutes time delay due to the huge distance to the comet). From then on ([[Media:???120.png|15:50]]) they and the mission control (MC) say "AAAAAAA". They stop this when the news should be there - the NOW ([[Media:???122a.png|16:05]]) - and everybody holds their breath indicated by [...] - also MC. Finally ([[Media:???125.png|16:25]]) they and MC become proud (along with Earth) when Philae announces ''I got you a comet.'' It should have stopped there but as Philae bounced around, they then becomes anxious again [[Media:???128.png|16:40]], and then this changes to nervous [[Media:???129.png|16:45]] (switching those emotions with MC). And then suddenly ([[Media:???130.png|16:50]]) it is no longer US Scientists but just plain Scientists - that are nervous. It stays like this during the last few pictures, although they again become anxious, but when Philae announces ''I did it'', they drink wine as indicated with "[wine]" in the report from the second to last picture ([[Media:???134.png|17:10]]).

Randall has written "A big thank-you to [https://twitter.com/elakdawalla Emily Lakdawalla] for help and advice on this comic" in the xkcd page header for [http://www.xkcd.com/1446/ Landing], revealing the possible source of his near real-time data.

At [[Media:???124.png|16:20]] the status report had announced a big '''Yes''' to the questions "Have we landed on a comet" and "Do harpoons work on comets". According to [http://www.bbc.com/news/science-environment-30026398 BBC News], the harpoons did, however, not fire as planned and the lander may have landed, bounced off, and landed again. This would explain the change in "Do harpoons work on comets" to "Don't know" at [[Media:???127.png|16:35]] and the change in "Have we landed on a comet?" to "Yes, at least once" at [[Media:???130.png|16:50]]. According to [http://www.nytimes.com/2014/11/13/science/space/european-space-agencys-spacecraft-lands-on-comets-surface.html?_r=0 The New York Times], radio contact with Philae fluctuated, which would explain the "Anxious", "Nervous", and "Confused" statuses around that time. In the end the lander did land and whereas the Do harppons work status did not change, so did the have we landed on a comet which changed back to '''Yes''' at [[Media:???134.png|17:10]].

The lander bounced three times and ended up in a place where the solar panels where mainly in the shadow. This resulted in the lander shutting down when its own battery ran out of power after only 2-3 days on the ground. This seemed sad, as there was only a small chance that the seasons on the comet would change so that the panels would later receive sun again. However, in the few hours that Philae had on the ground, it still managed to analyze the surface and obtain a lot of useful data - so that part of the mission was still a success already. This all happened after the comic stopped updating.

On June 13, 2015, it was announced that signals had been received on earth indicating that Philae had awoken and that the solar panels were functioning. Ironically, had Philae landed in a place originally out of shadow, it would have already failed before this time (due to overheating), so it was actually fortunate that it landed as it did and would be able to operate during the time that the comet would be closer to the sun. To celebrate the lander's revival, Randall updated the comic, depicting the lander saying "Hi." on the comet's surface.

The comic title was originally "???" (probably to not give away too early what the comic was about), but changed to "Landing" when Randall came on live at five in the morning EST. At that moment the title text also changed from "..." to "[LIVE]". It was also then that the timestamps' timezone switch. At 5:00 AM (EST) the time stamp in the picture naming scheme switched from EST to {{w|Coordinated Universal Time|UTC}} as used in ESA's time keeping, resulting in a jump from [[Media:???53.png|04:55]] to [[Media:???54.png|10:00]] without actually any such delay between the two pictures.

There were however a few pictures with more than 5 minutes of delay (about 11 times five minutes without an update in total during the "live" transmission). The update seemed to have stopped after 137 pictures at 17:15 UTC, 12 hours and 15 minutes after the first picture. (The first picture has number 0, so the last had number 136). But later, sometime after 17:15 UTC, the counter for the last picture was increased to 142 (143 pictures in total), so maybe Randall inserted 6 extra pictures later - however he must then have changed the numbers on the pictures, since the last picture remained the same until mid-June, but with number 142 instead of 136. It is thus now difficult to find out which pictures would have been added later. However, eight pictures were not included in the original table with the [[#Frame by Frame Breakdown|Frame by Frame Breakdown]] below. So it must have been some of those missing pictures that were added later - maybe all of them, as the last three may already have been added before the last picture was released (All 143 pictures are included in the flip-book gif image shown here above). But even 143 pictures at 5 minutes intervals only spans 11 hours and 50 minutes, thus there are still five ''5 minute intervals'' without any picture. See which in the [[1446: Landing/Frame by Frame Breakdown|table]].

==Frame by Frame Breakdown==
*Here is a [[1446: Landing/Frame by Frame Breakdown|link to a table]] with a frame by frame breakdown of all 143 pictures.
*Here is a [[1446: Landing/All pictures|page with all the pictures]] frame by frame.

==Transcript==
:[This transcript gives only the text of the most recent picture shown in the comic; that which is now shown when clicking to the comic on xkcd.]

:[Showing Philae on a comet.]
:Time Since Landing: 211 days
:Philae: Hi!
:[Status report at the bottom-right corner.]
:Status report:
::Rosetta: In space
::Philae lander: Hi!
::Mission control: '''!!!!!!!!!!!!!!!!'''
::Scientists: '''!!!!!!!!!!!!!!!!'''
::Have we landed on a comet?: '''''YES.'''''
::Sun: Warm
::Comet: Big
::Philae, where ''ARE'' you?: Home

:[For the '''full transcript''' of all 143 pictures see '''[[1446: Landing/Transcript]]'''.]

==Trivia==
*There appears to be a brief error between 02:35 and 02:45, where the time until lander separation is shown as 1 hour, counting down to 50 minutes, before being corrected to 75 minutes at 02:50.
**Since this was supposed to be during the "non-live" section before Randall got up (and got live) it is not sure whether this was a "real" mistake, or if he was up anyway, and corrected this timing error when he discovered the plans had change during the approach flight.

{{comic discussion}}
[[Category:Dynamic comics]]
[[Category:Space]]
[[Category:Comics with color‏‎]]
[[Category:Comics featuring Cueball‏‎]]
[[Category:Animals‏‎]]