Blending does not seem to work with the TextPrinter.
I found this old thread: http://www.opentk.com/node/1353
This is akin to using new TextPrinter(TextQuality.Medium), only with four times the memory consumption. Better to switch to TextQuality.Medium instead.
I didn't understand what you meant by this Fiddler : I'm already using TextPrinter(TextQuality.Medium) and not getting blending, so do I need to make the code changes suggested?