The original CBC logo, designed by École des Beaux Arts student Hortense Binette and used between 1940 and 1958, featured a map of Canada (and from 1940 to 1949, Newfoundland) and a thunderbolt design used to symbolize broadcasting.
In 1958, the CBC logo was redesigned for use at the end of network programs. Designed by scale model artist Jean-Paul Boileau, it consisted of the legends "CBC" and "Radio-Canada" overlaid on a map of Canada. For French programming, the "Radio-Canada" was placed on top.
The "Butterfly" logo was designed for the CBC by Hubert Tison in 1966 to mark the network's progressing transition from black-and-white to colour television, much in the manner of the NBC peacock logo. It was used at the beginning of programs broadcast in colour and was used until all CBC television programs had switched to colour. A sketch on the CBC Television program Wayne & Shuster once referred to this as the logo of the "Cosmic Butterfly Corporation."
The fourth CBC logo, known internally as "the gem", was designed for the CBC by graphic artist Burton Kramer in December 1974, and it is the most widely recognised symbol of the corporation. The main on-air identification featured the logo kaleidoscopically morphing into its form while radiating outward from the centre of the screen on a blue background. This animated version, which went to air in December 1974, is also known colloquially as "The Exploding Pizza". The appearance of this logo marked the arrival of full-colour network television service. The large shape in the middle is the letter C, which stands for Canada; the radiating parts of the C symbolize broadcasting, and the blue circle the logo was placed in represented the world, so the entire CBC logo, according to Kramer, represented the idea of "Canada broadcasting to the world". The original theme music for the 1974 CBC ident was a three-note woodwind orchestral fanfare accompanied by the voiceover "This is CBC" or "Ici Radio-Canada". This was later replaced by a different, and more familiar 11-note woodwind orchestral jingle, which was used until December 31, 1985.
The updated one-colour version of the gem/pizza logo, created by Hubert Tison and Robert Innes,] was introduced on January 1, 1986, and with it was introduced a new series of computer graphic-generated television idents for CBC and Radio-Canada. These idents consisted of different background colours corresponding to the time of day behind a translucent CBC gem logo, accompanied by different arrangements of the CBC's new, synthesized five-note jingle. The logo was changed to one colour, generally dark blue on white, or white on dark blue, in 1986. Print ads and most television promos, however, have always used a single-colour version of this logo since 1974.
In 1992, CBC updated its logo design to make it simpler and more red (or white on a red background). The new logo design, created by Swiss-Canadian design firm Gottschalk + Ash, reduces the number of geometric sections in the logo to 13 instead of the previous logo's 25, and the "C" in the centre of the logo became a simple red circle. According to graphic designer Todd Falkowsky, the logo's red colour also represents Canada in a symbolic way. With the launch of the current design, new television idents were introduced in November that year, also using CGI. Since the early 2000s, it has also appeared in white (sometimes red) on a textured or coloured background. It is now CBC/Radio-Canada's longest-used logo, surpassing the original incarnation of the Gem logo and the CBC's 1940 logo.
For complete CBC info, please visit: https://en.wikipedia.org/wiki/Canadian_Broadcasting_Corporation