The Warner Bros company began in 1918 when four brothers started a business in television and film. However, the logo wasn't seen until 1923 and the colored variation wasn't put to use until 1948.  The colored variation shown above is a commemorative logo that was introduced in 2012 for the company's 90th anniversary. The logo uses custom typeface and while there are different variations of the logo it has remained consistent with design and font through the years.  When I was a kid I watched a lot of Looney Tunes so every time I see this logo I imagine Bugs Bunny standing next to it with a carrot in hand.

info from - http://famouslogos.net/warner-bros-logo/