This article discusses color operations on digital images, using the new ColorMatrix class provided by GDI+. The ColorMatrix is a welcome addition to the GDI library, especially with the increase in demand of digital imaging applications, as more and more consumer products are made available. This class, as well as many other new GDI classes, provide more control to the developer and reduce dependence on 3rd party applications such as LEAD tools, and others. Some basic knowledge of matrix operations (multiplication, addition, etc), the RGBA colorspace and GDI+ is assumed.

http://www.codeproject.com/KB/GDI-plus/colormatrix.aspx