Google has had many logos since its renaming from BackRub. The current official Google logo was designed by Ruth Kedar, and is a wordmark based on the Catull typeface. The company also includes various modifications and/or humorous features, such as cartoon modifications of their logo for use on holidays, birthdays of famous people, and major events, such as the Olympics. These special logos, some designed by Dennis Hwang, have become known as Google Doodles.
In 1998, Sergey Brin created a computerized version of the Google letters using the free graphics program GIMP. The typeface was changed and an exclamation mark was added, mimicking the Yahoo! logo. "There were a lot of different color iterations", says Ruth Kedar, the graphic designer who developed the now-famous logo. "We ended up with the primary colors, but instead of having the pattern go in order, we put a secondary color on the L, which brought back the idea that Google doesn't follow the rules."
In 2010, the Google logo received its first major and permanent overhaul since 1999. The new logo was first tested in November 2009, and was officially launched on May 6, 2010. It utilises an identical typeface to the previous logo, but the "o" is distinctly more orange-colored in place of the previously more yellowish "o", as well as a much more subtle shadow rendered in a different shading style.
The first Google Doodle was in honor of the Burning Man Festival of 1998. The doodle was designed by Larry Page and Sergey Brin to notify users of their absence in case the servers crashed. Subsequent Google Doodles were designed by an outside contractor, until Larry and Sergey asked then-intern Dennis Hwang to design a logo for Bastille Day in 2000. Hwang has been designing the Google Doodles ever since.
Google doodles have been produced for the birthdays of several noted artists and scientists, including Andy Warhol, Albert Einstein, Leonardo da Vinci, Rabindranath Tagore, Louis Braille, Percival Lowell, Edvard Munch, Nikola Tesla, Béla Bartók, René Magritte, John Lennon, Michael Jackson, Robert Moog, Akira Kurosawa, Satyajit Ray, H. G. Wells, Freddie Mercury, Samuel Morse, Hans Christian Ørsted, Mahatma Gandhi, Dennis Gabor, Constantin Brancusi, Antonio Vivaldi, Abdel Halim Hafez, Jules Verne and Leonhard Euler, among others. Additionally, the featuring of Lowell's logo design coincided with the launch of another Google product, Google Maps. Google doodles are also used to depict major events at Google, such as the company's own anniversary. The celebration of historical events is another common topic of Google Doodles including a Lego brick design in celebration of the interlocking Lego block's 50th anniversary. Some Google Doodles are limited to Google's country specific home pages while others appear globally.
On February 14, 2007, Valentine's Day, the Google doodle featured a chocolate-dipped strawberry that combined the second "g" and the "l" as its green stem. This design gave the appearance that the "l" was missing, thereby displaying "Googe". In response to several speculations the Official Google Blog, responded: "When you look at the logo, you may worry that we forgot our name overnight, skipped a letter, or have decided that 'Googe' has a better ring to it. None of the above. I just know that those with true romance and poetry in their soul will see the subtlety immediately. And if you're feeling grouchy today, may I suggest eating a strawberry."
Google was criticized in 2007 for not featuring versions of the Google logo for American patriotic holidays such as Memorial Day and Veterans Day. That year, Google featured a logo commemorating Veterans Day.
Google Doodles violate a long accepted tenet of brand management: that a logo must be respected and used correctly and consistently at all times. A constantly changing logo was thought to reduce brand equity. While this may be true of many brands, Google has successfully defied the orthodoxy; the Google logo has been noted for the constant interactive engagement that attracts the attention of the press as well as general public notice.
Interactive and video doodles
On May 21, 2010, the 30th anniversary of the arcade game Pac-Man, Google unveiled worldwide their first interactive logo, created in association with Namco. Anyone who visited Google could play Pac-Man on the logo, which featured the letters of the word 'Google' on the Pac-Man maze. The logo also mimicked the sounds the original arcade game made. The "I'm Feeling Lucky" button was replaced with an "Insert Coin" button. Pressing this once enabled you to play the Pac-Man logo. Pressing it once more added a second player, Ms. Pac-Man, enabling 2 players to play at once, controlled using the W,A,S,D keys, instead of the arrows as used by Player 1. Pressing it for a third time performed an "I'm Feeling Lucky" search. It was then removed on May 23, 2010, initially replacing Pac-Man with the normal logo. Later on that day, Google released a permanent Google Pac-Man site, due to the popular user demand for the playable logo.
On September 6, 2010, Google added another interactive logo, which consisted of numerous coloured balls that fly near a cursor. On February 8, 2011, Google ran one of its most interactive Doodles in honor of Sci-Fi writer Jules Verne's 183rd birthday. "Pulling" on a lever enabled viewers to get a Nautilus submarine's view undersea of everything from divers to treasure to sea creatures, including a coral formation in the shape of the logo.
On October 8, 2010, Google ran its first animated doodle, a short music video of "Imagine" to commemorate John Lennon's 70th birthday. Similarly, Freddie Mercury's 65th birthday was celebrated on September 5, 2011, with an animated clip set to "Don't Stop Me Now". On April 15, 2011, Google sported the first video doodle, commemorating Charlie Chaplin's 122nd birthday. This doodle was a black and white YouTube video that, when clicked upon, started playing before redirecting to the usual Google search featuring the doodle's special occasion. All parts in this short film were played by the Google doodle team, and special behind-the-scenes footage was to be found on the Google blog.
Google displayed an interactive electric guitar doodle starting June 9, 2011, to celebrate the 96th birthday of Les Paul.
Apart from being able to hover the cursor over the doodle to strum the strings just like one of Les Paul's Gibson guitars, there was also a keyboard button, which when enabled allowed interaction with the doodle via the keyboard. The doodle still maintained some resemblance to the Google logo. In the U.S, the doodle also allowed the user to record a 30 second clip, after which a URL is created and can be sent to others. The doodle remained on the site an extra day due to popularity in the US. It now has its own page linked to the Google Doodles archives.
On June 15, 2011, Google displayed images updated almost in real time of an ongoing total lunar eclipse, along with a scroll bar allowing visitors to view images from the entire duration of the event. Images were captured from cameras in places where the eclipse was visible including South Africa, Dubai and the Canary Islands.
On November 23, 2011, Google celebrated the 60th anniversary of Stanislaw Lem's first book, The Astronauts, by creating an interactive logo using concepts and illustrations from The Cyberiad. August 6 and October 12 of the same year also included interactive doodles – the former date, Lucille Ball's 100th birthday, made the Google logo a television set playing clips of I Love Lucy. The latter date, Art Clokey's 90th birthday, made the Google logo into interactive versions of Gumby characters.
On May 23, 2012, Google's logo changed into a playable synthesizer in honor of Robert Moog's 78th birthday. On June 23, in commemoration of Alan Turing's 100th birthday, Google's logo became an interactive Turing Machine. 
On August 7, 2012, Google's logo changed into a playable set of hurdles as part of the celebration of the 2012 London Olympics. This was followed with an interactive Google Doodle of a basketball game, canoe and soccer.
Google holds a Doodle4Google competition for students in grades K–12 to create their own Google doodle. Winning doodles go onto the Doodle4Google website, where the public can vote for the winner, who wins a trip to the Googleplex and the hosting of the winning doodle for 24 hours on the Google website. The competition originated in the United Kingdom, and now also exists in the United States. The competition was also held in Ireland in 2008. Google announced Doodle4Google competition for India in 2009 and the winning doodle was displayed on the Google India homepage on November 14. A similar competition held in Singapore based on the theme "Our Singapore" was launched in January 2010 and the winning entry was chosen from over 30,000 entries received. The winning design will be shown on Singapore's National Day on Google Singapore's homepage.
From time to time, Google shows a special colorless logo on a local homepage in recognition of a major tragedy, often for several days. The design was apparently first used on the Google Poland homepage following the air disaster that killed President Lech Kaczyński in April 2010. A few days later, the logo was used in China and Hong Kong to pay respects to the victims of the Qinghai earthquake.
On September 8, 2010, the doodle once again changed to a greyed-out Google logo that lit up with the standard Google colors as the first 6 letters of a search query were entered. It goes by the name of the Keystroke Logo.
Google's favicon until 2008 was a blue, uppercase "G" on white background. It was framed by a border with a red, blue and a green side. In 2008–2009 a new version was introduced. It showed the lowercase "g" from Google's official logo, colored in white and originally was intended to be a part of a larger set of icons developed for better scalability on mobile devices. This version included background areas colored in red, green, blue and yellow. It was based on a design by André Resende, a computer science undergraduate student at the University of Campinas in Brazil. He submitted it for a contest launched by Google in June 2008 to receive favicon submissions. From the Official Google Blog: "His placement of a white 'g' on a color-blocked background was highly recognizable and attractive, while seeming to capture the essence of Google". The current version, introduced in August 2012 still shows the small letter "g", but has a simple, light blue background colour.
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- Official Google logos
- Google style logos' online museum
- Dennis Hwang: The man behind Google Doodles
- Doodle History
- Top Google Doodles For London Olympics 2012