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