The +/- signs inside the magnifying glass have to little contrast against the magnifying glass. When I saw them next to each other in the epiphany toolbar, I misinterpreted the shadow of the loupe as a minus and thought that it is strange to have two "zoom out" icons on the toolbar.
Created attachment 150436 [details] blue large original size check wiki page for updated icon
Created attachment 150437 [details] blue 16 original size
I've re-designed the set. The glass is now blue with black insides so the blue is the main focus as well as contrasting with the frame and handle. It has been discussed with dfong for a few weeks, the results can be seen in full on the fedoraproject.org/wiki/Artwork/EchoDevelopment wiki page tomorrow. BenArnold
The new icons should be in todays snapshot.