Channel 4

1st Logo (November 2, 1982-October 11, 1996, November 2, 2007)
Logo: Eight blocks of different sizes but matching colors: blue, purple, yellow and green, with a single red bar, form the number "4" on a black BG. There's several animations on how this happens:
 * The logo, already formed, spins around, the blocks in turn spinning before setting back into place.
 * Hundreds of little blocks fly in from the top right of the screen. The camera pans across as they go off the bottom left and sets in the middle, where the blocks form the logo.
 * The blocks spin onto the screen from various places, setting and forming the logo in the center.
 * The logo, already formed, breaks apart into hundreds of blocks that fly off the bottom left screen. They reappear from the top right and set back to reform the logo.

Trivia:
 * The logo was animated by the defunct Los Angeles-based CGI company Bo Gehring and Associates, as there was no computer at the time that was able to animate the logo in the UK.
 * At the time, "Fourscore" was the shortest musical piece to be copyrighted, and a full version, originally played on launch day, was released as a single on vinyl records. The album's reverse side also featured a calmer, synthesized version of the jingle (not related in any way to the 1992 version), also composed by Dundas, called "Fourscore II". This version was used to accompany stills were there a technical fault, and was also used to fill up the time allotted for commercial breaks if a regions ITV franchise had not sold them enough commercials to fill the timeslot.
 * During the 1980's, back when there were no rules about advertising tobacco products on TV, an advert for Hamlet's cigars aired that was a parody of the 4 ident, though it was still produced and animated by the same company behind the standard logo.

Variants: There are various versions of this logo. Below are some examples:
 * These logos had unique variations for certain programs, such as American football (the blocks forming an American football player wearing a helmet) and Football Italia (a football strikes the formed logo, turning it into the colours of the Italian flag).
 * Christmas idents:
 * Christmas 1982: The animation of the logo is superimposed in a shiny background, of a Christmas bauble with several glowing lines.
 * Christmas 1983: Like in 1982, the animation is superimposed on a background, although this time consisting on a starry sky.
 * Christmas 1984: On a dark blue background with a snow floor, can be see a snowman in the shape of the Channel 4 logo. Snow constantly fall.
 * Christmas 1985-1986?: The animation goes as usual. However, the logo eventually gradually turn from multicolored to frozen at the end.
 * Christmas 1987: Essentially, the same ident, with just a Christmas version of the Fourscore theme.
 * Christmas 1988: We see a metallic version of the Channel 4 logo, while the screen constatly shows different glowing curves and lines appearing. Some glows appear in sync. with the Fourscore theme.

FX/SFX: The blocks forming the number "4".

Music/Sounds:
 * November 1982-November 1992:A bombastic four note fanfare called "Fourscore" composed by David Dundas, who also composed the regional ident music for ITV. Various versions of the jingle were used.
 * November 1992-October 1996: A new fanfare was introduced, based on the original one. It would feature various reprises of the same basic tune, usually accompanied by four chimes.This version was brought in to replace the original jingle, as it was costing the channel too much to keep in use - David Dundas was paid £3.50 every time the original jingle was used, amounting in him earning around £1000 a week.

Availability: Extinct. It partially returned for the Channel 4's 25th birthday in 2007, on some adverts on C4 and its sister channel E4.

Editor's Note: None.

2nd Logo (Unused) (1991)
Logo: On a black background, we see three CGI rectangles colored blue, red and yellow stretching and rotating in various directions, eventually forming a simplified "4". It stays still for a few seconds before rotating and stops again.

FX/SFX: CGI animation by award-winning designer/director Matt Forrest of Snapper Films.

Music/Sounds: A dramatic fanfare, followed by an announcer spiel.

Availability: Extinct. It was never transmitted on the main channel, as it would still use the 1982 ident.

Editor's Note: None.

3rd Logo (October 11, 1996-April 2, 1999)
Logo: We see live-action places. Suddenly, they blur, and four circles are quickly formed on the screen. They are arranged in various ways.

Variants:
 * Other idents had a more soft transition. The footage blurs as the four circles lands on it, with several waves coming from the circles.
 * Christmas Idents:
 * Christmas 1996: The footages center around Santa on different places. The animation of the circles is intact.
 * Christmas 1997: On a white BG, a lot of baby blue circles (with one containing the Channel 4 logo) are flashing. Sometimes turning purple, or being cut by white lines.

FX/SFX: The circles.

Music/Sounds: The noises of live-action end in either a whoosh or a bunch of synth sounds.

Availability: Extinct.

Editor's Note: None.

4th Logo (April 2, 1999-December 31, 2004)
Logo: Although varied, most of the idents featured a moving background made from a bunch of rectangles. Then, the number "4", now on a white square, is formed in a sort of way in the right. The animation continues while the announcer is present.

Variants:
 * April-December, 1999: These idents were created by Spin, and mostly featured the rectangles on same color tones, while the square with the number "4" was formed by a scanning pulse. Other versions had different fast-paced footages of places showing while the rectangles are moving.
 * December 1999-2001: These idents were created by STATIC. The lines now features more different shades, has the Channel 4 logo is shown in different ways rather than just being "scanned". Like before, fast paced footages can be seen, although this time in the same shades has the rectangles.
 * 2001-2004: Another idents created by STATIC. This time the animation was focused in different ambiances, rather than just the rectangles. The Channel 4 logo still have different ways to appear.
 * Christmas Idents:
 * Christmas 2000-2001?: While the bars are barely seen, a lot of snow is falling to the right. The same square appear, but showing a tree at first, then showing the Channel 4 logo. Red and light blue versions are known to be used.

FX/SFX: The background moving, and the "4" being formed by the background.

Music/Sounds: It depends on the variant shown.
 * April-December, 1999: The music theme was a remix of the track Upstream by d*note. A loud sound is heard when the Channel 4 logo is formed.
 * December, 1999-2001: Different kind of tunes focused around a calm theme.
 * 2001-2004: Different sort of synth tunes.

Availability: Extinct.

Editor's Note: None.

5th Logo (December 31, 2004-September 2015)
Logo: We see an area or a part of the environment. There is a giant "4" which is made up of an object depending on the variant.

Variants: There are many variants of this logo:
 * Tralfagar Square: We see some pigeons flying onto Tralfagar Square in London, capital of the U.K. and walking on a large Channel 4 logo on a plinth. The logo then squeezes itself and retracts, causing some of the pigeons to either fly away or die (not visibly).
 * Bowls: We see a group of people playing lawn bowls outside as hedges in the shape of the Channel 4 logo parts fly around. Most of them don't notice, but one elderly lady on a bench turns around to see the sights in front of her. The Channel 4 logo is briefly made out of the shadows of the levitating hedges.
 * Rollercoaster: The Channel 4 logo is briefly formed during a first-person rollercoaster ride.
 * Diner: The Channel 4 logo is briefly formed during a panning of a diner/motel.
 * Alien: A woman and a man donning a cowboy hat are stuck worried in a car as mysterious metal objects fly around them and form the Channel 4 logo twice.
 * 3D Week: We pan across a junkyard to see a forklift grabbing some broken cars. A stack of junk and the forklift itself briefly form the Channel 4 logo.
 * Homer: We see Homer Simpson (voiced by actor Dan Castellaneta) put a pack of Duff beer on his hammock, but the force created by him initially lying on it causes the cans to fly up onto the electrical lines. He screams and falls off the hammock, and climbs up a tree to try and retrieve the cans. Because of the cans being aluminum and connected to the electricity, every time he tries to grab them he gets electrocuted. Night falls, and he tries one last time to get the cans. The shock causes one of them to open, and he tries drinking the can and gets electrocuted at the same time. We pan out from the Simpsons' backyard to reveal that Homer has unwittingly caused Springfield to gain a power outage that briefly flashes and forms the Channel 4 logo.
 * April Fools Day: On April Fools Day 2011, versions of these would be shown on the day where everything on screen that would make up the 4 logo is non-existent, turning the normal idents into plain old panoramic shots.

Trivia: The Simpsons Homer ident was a unique animation commissioned by Channel 4 and produced by Gracie Films. The animation from this ident was worked into the couch gag for the season 25 episode 'Specs and the City' with some alterations (rather than the original hammock scene, Homer is watching the Super Bowl and discovers that Bart threw the pack of Duff onto the power lines outside, leading into the animation from the ident), and whilst the lighting effects during the power outage scene are altered to remove the giant 4 logo, it can still be clearly seen in the street outlines if you look closely enough. After the 2015 rebrand, this episode is now the only way to see said ident broadcast on TV. The Rollercoaster variant is entirely filmed at a unknown amusement park somewhere in California, US.

FX/SFX: Depending on the variant used. Quite impressive, resembling the original 1982 idents.

Music/Sounds: Depending on the logo variant shown.

Availability: Extinct, as Channel 4 rebranded the logo in September 2015. Between this time and mid 2017, the new idents, bordering on the surreal, no longer featured the full 4 logo, and it didn't feature on the channel outside of print adverts in magazines and the Channel 4 News. Around the middle of 2017, program adverts and break bumpers were reworked to have the 4 logo visible for around a second in one form or another.

Editor's Note: The Homer variant may get to some people who haven't seen it before, but it's funny nonetheless.

6th Logo (September 2015 - October/November 2017)
Logo: We see one of 4 different surreal footages (which are shown in different lenghts). The Channel 4 logo is not directly seen, but instead, their parts are seen in different places around.

Variants: Other idents despicted the use of several blocks, which were primarly used for breakbumpers. Some of these idents included.
 * Several clock idents despicting different times of the day.
 * A Simpsons variant, aired before episodes of The Simpsons (although not all the time). In this one, the blocks, all colored yellow, keep moving towards different parts of the screen, along with a pair of circular shapes resembling eyes with small black pupils. Although new idents were introduced in late 2017, this version is still used in one way or another, either still being used before an episode, or as a bumper between episodes.
 * Another ident used for the coverage of Formula 1 motor racing.

FX/SFX: Live action, with CGI animation involved.

Music/Sounds: The Simpsons variant uses several loud saxophone notes that play in time to the blocks on screen moving.

Availability: Extinct. The Simpsons ident and the program bumpers are still used.

Editor's Note: None.

7th Logo (October/November 2017- )
Logo: As with the previous idents, there are numerous different versions that run in different lengths. All idents feature a large metal construct that vaguely resembles a man, built out of the various parts of the 4 logo.

Variants:
 * One version features the construct running alongside a group of Paralympic cyclists. It's eventually unable to keep up with them and stops by the side of the road, tiredly wheezing out the Fourscore tune, and collapses into pieces.
 * Another version features the construct walking up a mountain path that overlooks a distant town. It stands out on one of the peaks, facing the town, and blares the Fourscore, the sound and force of it causing havoc in the town, knocking a cyclist off their bike, causing animals to cry out, making a couple put on protective headsets, and a group of schoolchildren trying to stand against the force of the blast. The construct eventually stops, chuckles, and it cuts back to the kids toppling over in unison.

FX/SFX: Live action with CGI animation.

Music/Sounds: The background music for each ident is a simple string instrument track that borrows thematically from the channel's famous Fourscore tune from the first logo. The construct itself, in some of the idents, blares out the four note jingle, sounding akin to a foghorn.

Availability: Current.

Editor's Note: None.