vincebagna, you are so right... my mistake. Sorry, ice-boy.

Of course (I realise now) the shadows only appear in one of the render passes, so there is no combining of gamma-corrected passes in that part of the image in the Photoshop version.

I still don't see how the sphere could be expected to look the same in the two images, given that the separate elements are combined in different colour spaces.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)