with changing scenes, while a configuration change for 'noisy' video means the BBC no longer needed to use noise reduction techniques that often reduced the overall picture quality. The changes were welcomed by campaigners. 3D broadcasts Whenever the BBC has broadcast programmes or events in 3D, there were other technical changes made to the channel that accompanied it. The BBC's first broadcast of the Wimbledon finals in 2011 saw the screen resolution increased from the usual 1440 by 1080 to 1920 by 1080 between 13 June and 6 July. Equally, the same occurred for the 2011 Strictly Come Dancing final when the resolution was changed between 8 December 2011 and 5 January 2012. An increase to 1920 horizontal resolution was again observed on 30 May 2012 as part of the preparations of 2012's 3D broadcasts. Presentation The BBC HD channel only ever ran at its peak for an average of twelve hours a day, usually from mid afternoon, and was only ever allowed to expand beyond these hours for coverage of significant sporting events. When off air, the channel would broadcast a looped series of clips identified as the BBC HD Preview. These were of extended trailers and extracts for upcoming programmes on the channel separated by the channel's idents. These segments were also notable in their hourly broadcasts of the HD testcard, nicknamed Test Card X, overlaid with a BLITS audio test signal which allowed users to test and adjust their picture quality and position and the quality of their surround sound respectively. Equally, an audio visual synchronization animation was also broadcast hourly. The channel's presentation was unique from the other BBC channels and used its own style of programme idents and trailers. The channel originally used an ident that featured a diamond shape falling backwards down a stream before exploding to several more diamond shapes before taking its place back where it started to be back-lit over an announcement. These were used until 2009 when the presentation changed to a style featuring an ordinary scene which would become extraordinary when viewed through a rotating diamond shape. An example of this was a cat chasing pigeons that was seen as a lion when looked through the diamond shape. Original programme trailers and slides used the back-lit diamond shape as a base, while the 2009 versions used bright colours and textures inspired from the idents, for example the picnic blanket