== Gamma == 

 The article should mention that gamma encoding or its absence will have an effect on the appearance of the blended result. From what I've been able to gather recently, 

 * The PDF specifications say to use linear encodings both for blending and the subsequent compositing. 
 * That recent W3C spec says nothing, but its author has stated that (for Canvas and SVG at least), blending is to be performed in device space. 
 * That Photoshop has a "rarely used" mode for setting the gamma used for blending. 

 Anyone with deeper insight into these apps and technologies able to clarify the article more?