I'm using a 'Blend'-Background for my image. When I start the renderer, the screen output shows a smoother result than the saved file. Changing the image format produced no change (I normally use PNG and Targa Raw).
This is the on-screen-output of the renderer:

and this is the saved file:

Is this wanted? Is there a dithering process while showing the render on screen? Unfortunately, I prefer the on-screen version

Cheers
Thorsten