Expression Blend was code-namedSparkle, and originally the product was announced as Microsoft Expression Interactive Designer, before it was renamed Expression Blend in December 2006.
On January 24, 2007, Microsoft released the first public Community Technology Preview of Expression Blend as a free download on their web site. The final version was released to manufacturing along with other Expression products on 30 April 2007. The RTM news was announced at Microsoft's MIX 07 conference for web developers and designers. Expression Blend Service Pack 1 was released in November 2007. Expression Blend requires .NET Framework 3.0. Expression Blend and Expression Web are also available as part of the MSDN Premium subscription.
support for PSD and AI files, SketchFlow, TFS support and number of other significant improvements. Sketchflow is a user experience prototyping module implemented in Blend.
support for Silverlight 4 and WPF 4 while also remaining compatible with Silverlight 3 and WPF 3.5 SP1 applications. Other improvements and additions: shapes library, improved Photoshop file support, added pixel shader effects, path layout, transition effects, ListBox item transitions, Model-View-ViewModel pattern support, additional Behaviors, conditional Behaviors, sample data from CLR classes, design time resource resolution, easing functions for WPF 4, cleaner XAML, and .ZIP support for projects and templates. Support for Windows Phone 7 projects to Expression Blend 4 Release Candidate.
Name changed to "Blend for Visual Studio 2012". Released alongside the Windows 8 & Visual Studio 2012 RTMs. Includes support for WPF version 3.5, 4.0 and 4.5, Silverlight 4.0 and 5.0, SketchFlow, and Blend tools for Windows 8.