https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&feedformat=atom&user=162.158.150.64explain xkcd - User contributions [en]2026-04-16T05:01:44ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=1335:_Now&diff=1441071335: Now2017-08-16T10:51:26Z<p>162.158.150.64: /* Web */</p>
<hr />
<div><div class="plainlinks"><br />
{{comic<br />
| number = 1335<br />
| before = ''Explainxkcd note: The image below is accelerated to show a full day's spin in approximately 10 seconds. The actual comic completes one revolution per day. <br/>For the current state, see [http://xkcd.com/now/ http://xkcd.com/now]''<br />
| date = February 26, 2014<br />
| title = Now<br />
| image = now.gif<br />
| titletext = This image stays roughly in sync with the day (assuming the Earth continues spinning). Shortcut: [http://xkcd.com/now xkcd.com/now]<br />
}}<br />
</div><br />
<br />
==Explanation==<br />
The picture is divided in 24 segments representing the 24 hours of the day. At noon and at midnight the break between segments is indicated by the tip of a dark grey triangle.<br />
<br />
The picture rotates by 3.75 {{w|degree (angle)|degrees}} every 15 minutes, as does the Earth, so that it is constantly up to date in showing which regions are currently at which times of day. The picture change seems to happen half-way through a 15-minute time increment (that is, at 7½, 22½, 37½, and 52½ minutes after each hour), so that the picture is always correct for the nearest multiple of 15 minutes.<br />
<br />
The map projection of the earth in the middle of the picture shows an {{w|azimuthal equidistant projection}} with the {{w|South Pole}} in the center. This is unusual, as the projection typically puts the north pole in the center, but necessary in order for it to rotate clockwise. [[Randall]] was playing on projections before in [[977: Map Projections]].<br />
<br />
The list of cities and countries doesn't match the map exactly - notice how the continent of Australia is shifted counterclockwise of the words "most Australian cities". This is because the map is centered relative to the {{w|time zone}}s and the local variations therein. The map shows the configuration of time zones with respect to {{w|daylight saving time}} (also known as summer time) at the time of the comic's initial release (February 2014); it was being observed in parts of Australia, New Zealand, Brazil, and other countries not named in this comic. If the map were to stay accurate through the year, the location of place names would have to move over the next few months as parts of the southern hemisphere went off DST and parts of the northern hemisphere went onto it; however, the map failed to change on the morning of March 9 as it should have (to recognize the start of DST in North America).<br />
<br />
In many countries "{{w|business hours}}" are considered to be from 9&nbsp;am to 5&nbsp;pm. With some exceptions, including emergencies, it is generally considered rude to place a {{w|telephone}} call to someone's residence during the hours when most people are asleep; Randall portrays this time period as extending from 10 pm to 8 am. This may be a reference to the 10 pm "cutoff" time [http://www.youtube.com/watch?v=L0WeQJW-H3Y discussed] in an episode of "Curb Your Enthusiasm."<br />
<br />
On midnight at UTC we can see this situation:<br />
*00:00 UTC {{w|Greenwich Mean Time}}<br />
::UK, Portugal<br />
::West Africa<br />
*01:00 UTC {{w|Central European Time}}<br />
::Most of central Europe<br />
::Nigeria, and many more countries belonging to the {{w|West Africa Time}} zone<br />
*02:00 UTC {{w|Eastern European Time}}<br />
::Eastern Europe, many countries like Bulgaria, Romania or Greece<br />
::The {{w|Levant}}<br />
::Egypt<br />
*03:00 UTC {{w|UTC+03:00}} (East Africa Time, Eastern Europe Forward Time, and Arabia Standard Time)<br />
::Ethiopia, Kenya, Madagascar, Somalia, and more<br />
::Kaliningrad and Belarus<br />
::Iraq, Kuwait, Saudi Arabia, and more.<br />
::Iran is at {{w|Iran Standard Time}}, using an offset of UTC+03:30<br />
*04:00 UTC {{w|UTC+04:00}}<br />
::{{w|Moscow Time}}<br />
::United Arab Emirates, Mauritius, and more<br />
::Afghanistan is at {{w|Time in Afghanistan}}, using an offset of UTC+04:30<br />
::Iran is at {{w|Iran Standard Time}}, using an offset of UTC+03:30<br />
*05:00 UTC {{w|UTC+05:00}}<br />
::Pakistan, Western Australia, Maldives and some France former colonies.<br />
::Afghanistan is at {{w|Time in Afghanistan}}, using an offset of UTC+04:30<br />
::India and Sri Lanka using {{w|UTC+05:30}}<br />
::Nepal is using a much more odd offset at {{w|UTC+05:45}}<br />
*06:00 UTC {{w|UTC+06:00}}<br />
::Bangladesh, Bhutan...<br />
::UK {{w|British Indian Ocean Territory}}<br />
::Russia at {{w|Yekaterinburg Time}}, also Kazakhstan and Kyrgyzstan<br />
::China only use {{w|Time in China|one time zone}} (+08:00) but Xinjiang and Tibet unofficially use +06:00 <br />
::India and Sri Lanka using {{w|UTC+05:30}}<br />
::Nepal is using a much more odd offset at {{w|UTC+05:45}}<br />
*07:00 UTC {{w|UTC+07:00}}<br />
::South-east Asia like Cambodia, Indonesia, Thailand, Vietnam, and more<br />
::Christmas Island belonging to Australia<br />
::Russia is also using the {{w|Omsk Time}}<br />
*08:00 UTC {{w|UTC+08:00}}<br />
::Western Australia<br />
::China uses only {{w|Time in China|one time zone}} while the country spans about five.<br />
::Singapore<br />
::Philippines<br />
::Perth<br />
*09:00 UTC {{w|UTC+09:00}}<br />
::Japan<br />
::The Koreas<br />
*10:00 UTC {{w|UTC+10:00}}<br />
::Brisbane and the Australian Capital Territory, New South Wales, Queensland, Tasmania and Victoria<br />
::US: Guam and Northern Mariana Islands<br />
*11:00 UTC {{w|UTC+11:00}}<br />
::Micronesia, New Caledonia, Solomon Islands, Vanuatu<br />
::Russia {{w|Vladivostok Time}}<br />
*12:00 UTC {{w|UTC+12:00}} or {{w|UTC−12:00}}<br />
::Kamchatka (a Russian peninsula at the east Siberia), Kiribati, Marshall Islands, Nauru, Tuvalu and more<br />
*13:00 UTC {{w|UTC+13:00}} or {{w|UTC−11:00}}<br />
::New Zealand, Kiribati, Tonga<br />
*14:00 UTC {{w|UTC+14:00}} or {{w|UTC−10:00}}<br />
::Hawaii, Samoa<br />
::French Polynesia, Cook Islands, and more<br />
::Line Islands, belonging to Kiribati<br />
*15:00 UTC {{w|UTC−09:00}}<br />
::{{W|Time in Alaska|Alaska}} (some islands of Alaska is at -10:00 and a few city's are at -08:00)<br />
::French Polynesia <br />
*16:00 UTC {{w|UTC−08:00}} or {{w|Pacific Time Zone}}<br />
::US West Coast<br />
::Canada or (British Columbia and Yukon)<br />
::Mexico (Baja California)<br />
*17:00 UTC {{w|UTC−07:00}} or {{w|Mountain Time Zone}}<br />
::US: Denver, and much more<br />
::Canada: Alberta (Calgary, Edmonton), British Columbia, more<br />
*18:00 UTC {{w|UTC−06:00}} or {{w|Central Time Zone}}<br />
::Mexico, Chile, Ecuador, Nicaragua and more<br />
::US: Chicago, Texas except of some most westernmost counties, and many more<br />
*19:00 UTC {{w|UTC−05:00}} or {{w|Eastern Time Zone}}<br />
::Eastern Canada like Ontario or Quebec<br />
::US East Coast including New York and Florida.<br />
::But also Cuba, Haiti, Panama and much more countries<br />
*20:00 UTC {{w|UTC−04:00}} or {{w|Atlantic Time Zone}}<br />
::Canadian Maritimes: New Brunswick, Prince Edward Island, Nova Scotia. (Newfoundland uses {{w|UTC-03:30}})<br />
::Chile<br />
::Greenland<br />
::Most of the Caribbean Islands.<br />
*21:00 UTC {{w|UTC−03:00}}<br />
::Coastal Brazil, Argentina, Uruguay, French Guiana, the UK Falkland Islands, and more<br />
*22:00 UTC {{w|UTC−02:00}}<br />
::UK: South Georgia and the South Sandwich Islands<br />
::Brazil: Fernando de Noronha<br />
*23:00 UTC {{w|UTC−01:00}}<br />
::Cape Verde<br />
::Azores (part of Portugal)<br />
<br />
==Technical notes==<br />
When first posted, the picture was exactly 12 hours off. Somewhere around 5:10 UTC, this was fixed. The original version also included a listing for Inland Brazil; this could have created a conflict with US East Coast when Daylight-Saving Time begins in the US, and it has been removed.<br />
<br />
The names used for the image files refer not to {{w|Universal Time|UTC (Universal Time)}} as one might expect but rather to the time exactly 12 hours off of that. The name of the image file linked from the page matched Universal Time during the first few hours, but the file-naming scheme did not change when the comic was corrected.<br />
<br />
==Transcript==<br />
:[The comic is a moving circle with a static outer ring.]<br />
<br />
:[The outermost part of the static ring is divided in 22 segments representing the 24 hours of the day. The Noon (11 AM - 1 PM) and Midnight (11 PM - 1 AM) segments cover two hours which are not segmented. The ring is divided so it is yellow from 6 AM to 6 PM and dark grey on the other half.]<br />
::Noon - 6 PM - Midnight - 6 AM<br />
<br />
:[The innermost part of the static ring is light grey and divided in two sections that cower from 9 AM to 5 PM and from 10 PM to 8 AM respectively. They contain descriptions of the time intervals.]<br />
::Business hours (9-5)<br />
::Rude to call<br />
<br />
:[The rest of the image consist of a rotating part.]<br />
<br />
:[On the innermost part of the circle is the Earth as seen from the south pole. Each continent has a different color. The colors are<br />
:*Europe: Red<br />
:*Africa: Cyan<br />
:*Asia: Green<br />
:*Oceania: Purple<br />
:*North America: Blue-violet<br />
:*South America: Olive green<br />
:*Antarctica (The south pole): Light grey<br />
<br />
:[Two segmented rings circle the map - these give the names of the continents (not the Antactica) and the color of the ring match the color of the continent on the map. Each segment cover the part of the map with the given continent. The one with Europe is merged with the one for Asia - and the color also merges from red to green along Turkey and Russia where the transition from Europe to Asia occurs.]<br />
<br />
:[On the inner ring are the names of the following continents (white text on a segment with the color of the continent)]<br />
::Africa<br />
::Oceania<br />
::South America<br />
<br />
:[On the second of these rings are the names of the following continents (white text on a segment with the color of the continent)]<br />
::Europe Asia <br />
::North America<br />
<br />
:[On the outermost ring of the moving circle are written names of regions, countries and cities of the Earth over the part of the map in which time zone they belong. All the text is color coded to match the color of the continent they belong to as given on the central map. The text is written in four lines. Below the names are sorted by color and reading from left to right first - and only sorting top to bottom if needed.]<br />
<br />
:[Europe - Red text:]<br />
::UK - Most of Europe - Eastern Europe<br />
<br />
:[Africa - Cyan text:]<br />
::West Africa - Nigeria - Egypt - East Africa<br />
<br />
:[Asia - Green text:]<br />
::The Levant - Iraq - Iran - Moscow - Afghanistan - Pakistan - India - Southeast Asia - Java - China - Singapore - Philippines - Japan - The Koreas - Kamchatka<br />
<br />
:[Oceania - Purple text:]<br />
::Perth - Brisbane - Most Australian cities - New Zealand<br />
<br />
:[North America - Blue-violet text:]<br />
::Alaska - US West Coast - Denver - Mexico - Chicago - Texas - Eastern Canada - US East coast - Canadian Maritimes<br />
<br />
:[South America - Olive green text:]<br />
:: Coastal Brazil<br />
<br />
==Implementations==<br />
There are currently several implementations of the Now comic available for several different platforms:<br />
<br />
===Windows===<br />
A [https://github.com/leipert/xkcd-now-clock script] that automatically updates the wallpaper for the current time.<br />
<br />
===Android===<br />
An [https://play.google.com/store/apps/details?id=net.phillab.xkcd_now Android widget] version of the comic.<br />
<br />
===Web===<br />
A [http://www.xkcdnow.com/ web-based implementation] which also displays time zones. (Not working on 02017-08-16)<br />
<br />
A [http://c0la.s3.amazonaws.com/xkcd1335.html draggable] implementation (click&drag - left and right) (Not working on 02017-08-16)<br />
<br />
===Cross-Platform===<br />
An [https://github.com/BruceJohnJennerLawso/xkcd-Now/releases/tag/1.02 offline version of the comic] made using C++ and SFML.<br />
<br />
==Timed Links==<br />
[http://imgs.xkcd.com/comics/now/00h00m.png 00h00m] [http://imgs.xkcd.com/comics/now/00h15m.png 00h15m] [http://imgs.xkcd.com/comics/now/00h30m.png 00h30m] [http://imgs.xkcd.com/comics/now/00h45m.png 00h45m] [http://imgs.xkcd.com/comics/now/01h00m.png 01h00m] [http://imgs.xkcd.com/comics/now/01h15m.png 01h15m] [http://imgs.xkcd.com/comics/now/01h30m.png 01h30m] [http://imgs.xkcd.com/comics/now/01h45m.png 01h45m] [http://imgs.xkcd.com/comics/now/02h00m.png 02h00m] [http://imgs.xkcd.com/comics/now/02h15m.png 02h15m] [http://imgs.xkcd.com/comics/now/02h30m.png 02h30m] [http://imgs.xkcd.com/comics/now/02h45m.png 02h45m] [http://imgs.xkcd.com/comics/now/03h00m.png 03h00m] [http://imgs.xkcd.com/comics/now/03h15m.png 03h15m] [http://imgs.xkcd.com/comics/now/03h30m.png 03h30m] [http://imgs.xkcd.com/comics/now/03h45m.png 03h45m] [http://imgs.xkcd.com/comics/now/04h00m.png 04h00m] [http://imgs.xkcd.com/comics/now/04h15m.png 04h15m] [http://imgs.xkcd.com/comics/now/04h30m.png 04h30m] [http://imgs.xkcd.com/comics/now/04h45m.png 04h45m] [http://imgs.xkcd.com/comics/now/05h00m.png 05h00m] [http://imgs.xkcd.com/comics/now/05h15m.png 05h15m] [http://imgs.xkcd.com/comics/now/05h30m.png 05h30m] [http://imgs.xkcd.com/comics/now/05h45m.png 05h45m] [http://imgs.xkcd.com/comics/now/06h00m.png 06h00m] [http://imgs.xkcd.com/comics/now/06h15m.png 06h15m] [http://imgs.xkcd.com/comics/now/06h30m.png 06h30m] [http://imgs.xkcd.com/comics/now/06h45m.png 06h45m] [http://imgs.xkcd.com/comics/now/07h00m.png 07h00m] [http://imgs.xkcd.com/comics/now/07h15m.png 07h15m] [http://imgs.xkcd.com/comics/now/07h30m.png 07h30m] [http://imgs.xkcd.com/comics/now/07h45m.png 07h45m] [http://imgs.xkcd.com/comics/now/08h00m.png 08h00m] [http://imgs.xkcd.com/comics/now/08h15m.png 08h15m] [http://imgs.xkcd.com/comics/now/08h30m.png 08h30m] [http://imgs.xkcd.com/comics/now/08h45m.png 08h45m] [http://imgs.xkcd.com/comics/now/09h00m.png 09h00m] [http://imgs.xkcd.com/comics/now/09h15m.png 09h15m] [http://imgs.xkcd.com/comics/now/09h30m.png 09h30m] [http://imgs.xkcd.com/comics/now/09h45m.png 09h45m] [http://imgs.xkcd.com/comics/now/10h00m.png 10h00m] [http://imgs.xkcd.com/comics/now/10h15m.png 10h15m] [http://imgs.xkcd.com/comics/now/10h30m.png 10h30m] [http://imgs.xkcd.com/comics/now/10h45m.png 10h45m] [http://imgs.xkcd.com/comics/now/11h00m.png 11h00m] [http://imgs.xkcd.com/comics/now/11h15m.png 11h15m] [http://imgs.xkcd.com/comics/now/11h30m.png 11h30m] [http://imgs.xkcd.com/comics/now/11h45m.png 11h45m] [http://imgs.xkcd.com/comics/now/12h00m.png 12h00m] [http://imgs.xkcd.com/comics/now/12h15m.png 12h15m] [http://imgs.xkcd.com/comics/now/12h30m.png 12h30m] [http://imgs.xkcd.com/comics/now/12h45m.png 12h45m] [http://imgs.xkcd.com/comics/now/13h00m.png 13h00m] [http://imgs.xkcd.com/comics/now/13h15m.png 13h15m] [http://imgs.xkcd.com/comics/now/13h30m.png 13h30m] [http://imgs.xkcd.com/comics/now/13h45m.png 13h45m] [http://imgs.xkcd.com/comics/now/14h00m.png 14h00m] [http://imgs.xkcd.com/comics/now/14h15m.png 14h15m] [http://imgs.xkcd.com/comics/now/14h30m.png 14h30m] [http://imgs.xkcd.com/comics/now/14h45m.png 14h45m] [http://imgs.xkcd.com/comics/now/15h00m.png 15h00m] [http://imgs.xkcd.com/comics/now/15h15m.png 15h15m] [http://imgs.xkcd.com/comics/now/15h30m.png 15h30m] [http://imgs.xkcd.com/comics/now/15h45m.png 15h45m] [http://imgs.xkcd.com/comics/now/16h00m.png 16h00m] [http://imgs.xkcd.com/comics/now/16h15m.png 16h15m] [http://imgs.xkcd.com/comics/now/16h30m.png 16h30m] [http://imgs.xkcd.com/comics/now/16h45m.png 16h45m] [http://imgs.xkcd.com/comics/now/17h00m.png 17h00m] [http://imgs.xkcd.com/comics/now/17h15m.png 17h15m] [http://imgs.xkcd.com/comics/now/17h30m.png 17h30m] [http://imgs.xkcd.com/comics/now/17h45m.png 17h45m] [http://imgs.xkcd.com/comics/now/18h00m.png 18h00m] [http://imgs.xkcd.com/comics/now/18h15m.png 18h15m] [http://imgs.xkcd.com/comics/now/18h30m.png 18h30m] [http://imgs.xkcd.com/comics/now/18h45m.png 18h45m] [http://imgs.xkcd.com/comics/now/19h00m.png 19h00m] [http://imgs.xkcd.com/comics/now/19h15m.png 19h15m] [http://imgs.xkcd.com/comics/now/19h30m.png 19h30m] [http://imgs.xkcd.com/comics/now/19h45m.png 19h45m] [http://imgs.xkcd.com/comics/now/20h00m.png 20h00m] [http://imgs.xkcd.com/comics/now/20h15m.png 20h15m] [http://imgs.xkcd.com/comics/now/20h30m.png 20h30m] [http://imgs.xkcd.com/comics/now/20h45m.png 20h45m] [http://imgs.xkcd.com/comics/now/21h00m.png 21h00m] [http://imgs.xkcd.com/comics/now/21h15m.png 21h15m] [http://imgs.xkcd.com/comics/now/21h30m.png 21h30m] [http://imgs.xkcd.com/comics/now/21h45m.png 21h45m] [http://imgs.xkcd.com/comics/now/22h00m.png 22h00m] [http://imgs.xkcd.com/comics/now/22h15m.png 22h15m] [http://imgs.xkcd.com/comics/now/22h30m.png 22h30m] [http://imgs.xkcd.com/comics/now/22h45m.png 22h45m] [http://imgs.xkcd.com/comics/now/23h00m.png 23h00m] [http://imgs.xkcd.com/comics/now/23h15m.png 23h15m] [http://imgs.xkcd.com/comics/now/23h30m.png 23h30m] [http://imgs.xkcd.com/comics/now/23h45m.png 23h45m]<br />
<br />
{{comic discussion}}<br />
[[Category:Comics with color]]<br />
[[Category:Dynamic comics]]</div>162.158.150.64https://www.explainxkcd.com/wiki/index.php?title=1863:_Screenshots&diff=1426961863: Screenshots2017-07-15T22:28:25Z<p>162.158.150.64: screenshots in 1683:_Digital_Data</p>
<hr />
<div>{{comic<br />
| number = 1863<br />
| date = July 14, 2017<br />
| title = Screenshots<br />
| image = screenshots.png<br />
| titletext = For the final exam, you take a screenshot showing off all the work you've done in the class, and it has to survive being uploaded, thumbnailed, and re-screenshotted through a chain of social media sites.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Let's add a detailed bullet list explaining every point on the syllabus.}}<br />
<br />
The comic shows a syllabus of an introductory course on {{w|Screenshot|screenshots}}. Screenshots have become a common way of spreading and sharing content on social media like Tumblr and Twitter, particularly excerpts of text such as seen in the cartoon. This in turn has developed into a common language with unwritten rules; the comic imagines a world where such rules have become codified into best practices, able to be taught in classes.<br />
<br />
The image on the left shows an image of screenshots of text, along with what seems like annotations describing various ratios and dos and don'ts about making such screenshots. The right side shows the main points of the course, touching on topics that are relevant for making and publishing screenshots. Some of these guidelines are violated on a regular basis by people sharing screenshots on the internet, leading to impaired readability and the degradation of digital quality (see [[1683: Digital Data]]). <br />
<br />
The punchline of the comic describes a high attendance in the course (presumably many people are interested in how to take high-quality screenshots); however, the digital textbook only sold one copy, implying that the only attendee that bought the book was adept enough to distribute screenshots of the textbook content to the others, because of the information gathered from the class itself. In essence, the writer of the textbook has taught its students how to pirate his material, effectively putting himself out of a job.<br />
<br />
Detailed explanation of the headings on the right:<br />
<br />
{| class=wikitable<br />
! Heading<br />
! Explanation<br />
<br />
|-<br />
| Highlighting: What & How much?<br />
| This refers to highlighting text of particular interest in screenshots, as depicted on the left.<br />
<br />
|-<br />
| Aspect ratios<br />
| Again, depicted on the left. If a screenshot is too wide, it might be difficult to read, and/or it will not fit into thumbnails and social networking feeds. This leads to the screenshot being scaled down too much to be readable (see bottom left). An {{w|aspect ratio}} that is too tall would have similar effects, so in general it is better to stick to near-square aspect ratios (see bottom right of the left section). Some users change the aspect ratio when scaling with a very ugly result (see e.g. [[1187: Aspect Ratio]]).<br />
<br />
|-<br />
| Cropping: Pre- and Post-<br />
| This refers to {{w|cropping}} the image, that is, cutting away the irrelevant or unnecessary parts, leaving just the content one needs to communicate.<br />
<br />
|-<br />
| Whitespace<br />
| This section presumably deals with how to handle large blocks that lack content (or {{w|White space (visual arts)|whitespace}}, though not necessarily white).<br />
<br />
|-<br />
| Screenshots vs Links<br />
| For the most part it is recommended that one links to the original content, rather than publishing a screenshot of said content. In some situations it is advisable to opt for using screenshots, such as trying to catch attention on social media, or if the content in question has been removed from the original source, and one still wants to communicate the fact that it was published there.<br />
<br />
|-<br />
| Catching the right GIF frame<br />
| A {{w|GIF}} is a bitmap image format that was developed in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability. The format supports animations and is often used for short looping animations on the internet. They often employ a low {{w|frame rate}}, so that one might notice a funny or interesting frame during playback. The naïve approach is to press the 'Print Screen' button with careful timing, but in this manner it can be very challenging to capture the desired frame of any GIF that plays at a speed of greater than 5 frames per second. Presumably, the course introduces its students to special tools to get the job done, such as [https://ezgif.com/speed the EZgif website] or the [http://www.xtreme-lab.net/7gif/en/index.html downloadable 7GIF app]. <br />
|-<br />
| Snapchat and trust<br />
| {{w|Snapchat}} is a popular social networking application for mobile devices primarily used for sharing images and short videos. One of the main selling points is the transience of content posted. The idea is that as soon as one opens an image or video, a timer starts, and once it has expired the content is no longer accessible on the device. This has led to people sending sensitive content to their friends, thinking that they wouldn't be able to cause much harm, as the content is non-permanent. An obvious flaw in this model is the capability of modern mobile devices to take screenshots (usually available from shortcut keys), and thus permanently save the images to the phone's memory. Saving embarrassing images of one's friends, that they themselves meant as a transient joke, is a serious breach of trust, hence the heading.<br />
<br />
|-<br />
| Embarrassing background tabs<br />
| A common error when publishing screenshots is not checking thoroughly enough, and leaving content visible, that might be embarrassing. One such example is {{w|browser tab}}, which might feature content that the creator of the screenshot does not want others to see, such as a page about a sensitive disease one may have (e.g. {{w|AIDS}}) or {{w|pornography}}. Since tabs are small and disconnected from the main content, it is easy to miss such occurrences, which lead to situations such as [http://www.foxnews.com/politics/2017/06/10/lawmaker-mistakenly-hands-out-document-with-porn-references.html this one], where a politician handed out a document with background tabs to pornography websites.<br />
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|-<br />
| Spellcheck's red underlines<br />
| {{w|Spell checkers}} are designed to notify the writer of a document of spelling and grammatical mistakes in the text. This is usually done through the editor marking text it thinks is incorrect with an underline (usually red, but other colors may indicate different kinds of mistakes). Sometimes these mistakes are not relevant to the writer, such as when editing {{w|source code}} or using a spellchecker that is set to another language. Even if the corrections are relevant, however, one would not want the ugly red underlines on a screenshot. This section presumably deals with this problem.<br />
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| Security: Beware of URL tokens<br />
| {{w|Query string|URL tokens}} are pieces of code embedded in the {{w|URL}} of a website. If implemented well, these help identify a particular document or search query, and do not carry any sensitive security information. Insecure web-apps, however, may encode authentication information (such as {{w|Session_ID|session IDs}}, or even worse: usernames and passwords) in the URL, leading to a massive security risk on the part of someone whose screen might be visible to others. Screenshots allow anyone to easily read off these parameters, and possibly successfully impersonate the creator of the screenshot on a website. This is especially hard to notice to less technically inclined users, who might not know that, say, a session ID (a seemingly random jumble of characters), might be used to impersonate them.<br />
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|-<br />
| Redacting personal info<br />
| Somewhat related to the previous point: Screenshots might include personal information, such as indications of institutions one might work for, e-mail addresses, and the like, that one might not want to share with the world. This section presumably deals with ways of obscuring such information on screenshots.<br />
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| Useful browser modes<br />
| Using the {{w|Privacy mode|private browsing mode}} offered by most browsers helps with the previous point of keeping your personal information out of the screenshots because websites see you as logged out. Another helpful mode is the full screen browsing mode (usually F11) that will maximize the content to cover the whole screen, keeping the browser UI chrome out of the screenshots. This also helps with privacy, as it will keep the bookmarks on your browser toolbar from being visible, as well as your username if you're logged in Chrome, without having to crop the screenshots manually. Counterpointing with the final bullet on spotting fakes, the Inspect Element browser mode allows you to live-edit the HTML source of the webpage, allowing you to create more convincing fakes if that is your goal.<br />
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|-<br />
| Tradeoffs: PNG vs JPG<br />
| {{w|Portable Network Graphics|PNG}} and {{w|JPG}} are file formats with different {{w|image compression|image compression algorithms}}. JPG is widely used for encoding photographs, as it compresses real-world images to a fraction of their normal size without losing much quality. On artificial images with lots of sharp changes in contrast (such as text), however, JPG produces visible {{w|compression artifacts}} due to its {{w|lossy compression}}. For these, PNG is usually used, as it compresses large blocks of a single color, and repeating patterns efficiently, and due to it having a lossless option is able to encode text without artifacts, improving readability. PNG is usually superior for screenshots, as these are artificial images, but if the screenshot is of an actual photo (or a frame of a GIF or movie), JPG might yield lower file sizes at comparable quality. This tradeoff is presumably discussed under the heading.<br />
JPG images also have an attached {{w|EXIF}} data file, not present in PNG images, which may contain information about the device that the screenshot was taken on (especially "with", e.g. a camera) and thus be a potential privacy risk in some cases. However, EXIF metadata is not used with JPEG 2000.<br />
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|-<br />
| Watermark ethics<br />
| Many users and websites add {{w|watermarks}} to their original content (or even worse: their screenshots) to indicate where it came from. As depicted in [[1683: Digital Data]] this can lead to degradation of quality as watermarks are stacked on top of each other. It is generally considered okay to put a single unobtrusive watermark on one's own original work; anything other than that would be considered unethical.<br />
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|-<br />
| Spotting fakes<br />
| It is relatively easy to fake a screenshot in an image editing program such as {{w|GIMP}} or just editing the page source, making it seem like another organization or person is the original source of the content, possibly damaging their reputation. Some of these techniques are easily detectable by looking at the images {{w|metadata}} or correlating the contents of the screenshot with other sources.<br />
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|}<br />
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The title text once again refers to the continual re-screenshooting of data as seen in [[1683: Digital Data]], where the final examination consists of the students taking a screenshot good enough that it is still recognizable (and hopefully readable) after being re-compressed, re-screenshot and re-uploaded to various social networking sites, deteriorating its quality. This is quite a difficult task, considering the student only has control over the first screenshot, and subsequent screenshots could degrade the quality to any level. Hopefully the professor is aware of this and plans to perform the test under controlled conditions, as well as grade on a curve.<br />
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Previously were explored by Randall in [[1373: Screenshot]], [[1683: Digital Data]] and [[1815: Flag]]. This comic is one of a small set of comics with the same or almost the same title as another comic (with only the plural form of the word screenshot being the difference).<br />
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==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
:<big>Intro to Screenshots</big><br />
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:[The left side of the panel shows three images. The largest image is a screenshot of text with the middle section highlighted and margins and top and bottom rows marked with red lines and arrows. The two smaller images below are cropped versions of the screenshot in the first image: the left image has an incorrect "squashed" aspect ratio and a red X on it, while the right image has a correct aspect ratio and a green check mark.]<br />
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:[The right side of the panel:]<br />
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::<u>Syllabus</u><br />
:*Highlighting: What & how much<br />
:*Aspect ratios<br />
:*Cropping: Pre- and post-<br />
:*Whitespace<br />
:*Screenshots vs links<br />
:*Catching the right GIF frame<br />
:*Snapchat and trust<br />
:*Embarrassing backround tabs<br />
:*Spellcheck's red outlines<br />
:*Security: Beware URL tokens<br />
:*Redacting personal info<br />
:*Useful browser modes<br />
:*Tradeoffs: PNG vs JPG<br />
:*Watermark ethics<br />
:*Spotting fakes<br />
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:[Caption below the panel:]<br />
:My class on screenshots was a big hit, although for some reason I only ever sold one copy of the digital textbook.<br />
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{{comic discussion}}<br />
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[[Category:Comics sharing name|Screenshot02]]<br />
[[Category:Comics with color]]</div>162.158.150.64https://www.explainxkcd.com/wiki/index.php?title=Talk:386:_Duty_Calls&diff=140970Talk:386: Duty Calls2017-06-08T09:50:05Z<p>162.158.150.64: </p>
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<div>Doesn't look like anyone's touched this during its spotlight as the Incomplete Article of the Day. But really, what else can we say? [[Special:Contributions/199.27.128.66|199.27.128.66]] 03:06, 14 November 2013 (UTC)<br />
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Maybe how deeply compelling the "need" to fix something wrong on the Internet is? It's not just a plain correction.... it gnaws at you...[[Special:Contributions/108.162.219.8|108.162.219.8]] 03:17, 14 November 2013 (UTC)<br />
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Tried to flesh out/improve the analysis. Still needs some editing for clarity [I'm not sure how formal the tone of this wiki is supposed to be?] but hopefully it's an improvement on the previous edit. [[Special:Contributions/108.162.216.56|108.162.216.56]] 17:47, 14 November 2013 (UTC)<br />
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I think its good. Hits on all the points, unless anyone sees differently I think it adequately explains the comic. I think all the editing from here is flow and stylistic stuff. And that's minimal. --[[User:Lackadaisical|Lackadaisical]] ([[User talk:Lackadaisical|talk]]) 20:22, 14 November 2013 (UTC)<br />
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It's a Cunningham's law reference, guys, that's it. {{unsigned ip|141.101.106.155}}<br />
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The title "Duty Calls" has a double meaning. One that Cueball needs to go "fix" the internet and that he needs to "be" with his S/O. [[Special:Contributions/108.162.216.47|108.162.216.47]] 21:04, 26 August 2015 (UTC){{unsigned ip|127.0.0.1}}<br />
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I think this explanation misses the case when someone is ''factually'' wrong on the internet, and doesn't just have a different opinion. For example, when someone on Facebook "discovers" that the Mercator map projection is "wrong" and that the "true" one is Gall-Peters (true story), I believe even Randall would feel the need to say something. But of course, the border between factual errors and arguing is very thin... [[Special:Contributions/162.158.150.64|162.158.150.64]] 09:50, 8 June 2017 (UTC)</div>162.158.150.64