which version is correct?

In the SVG WG's familiar example of composite filters at
http://www.w3.org/TR/SVGFilterPrimer12/examples/filters01.svg ...

 

I recently had occasion to look a bit more closely. Four browsers make
reasonable attempts at pulling it off: Chrome, Opera, IE/ASV and FF4.

 

ASV and Chrome are fairly close to one another, with Opera's version being
darker and more "tubefy" like and FF's being considerably lighter. The
differences become much more apparent as the graphic is scaled to fill a
larger part of the screen (by, for example simply removing the part of the
code that specifies the size of the SVG as width="7.5cm" height="5cm" ). 

 

My question :  which version is closest to what the spec says? 

 

A meta-question: is the spec intended to nail such issues to such accuracy
that these browser differences will one day cease to exist, or is it
intended to give each implementer such freedom as to interpret the spec with
her own corporate flair?

 

Ultimately, if SVG is to be used for things like trademarks (or other things
requiring high precision reproducibility) , then a  trademark applicant may
need to cover a lot more bases in specifying the range of art that is sought
to be protected.

 

Thanks for sharing your opinions, as I'm not sure all will agree.

 

Cheers

David