My scanner apart from being crap also has a tendency to turn greys into blues so these upperparts tones are not accurate, especially when you compare them to the first photo below.
A real chameleon when it comes to changing colour. One minute it's as dark as a LBBG , the next it's like a YLG. The hood also varies in intensity depending on the light. In bright sunlight the hood can be reduced to a dirty brown wash but in failing light you suddenly realise just how heavily streaked it is.
Watched today standing side by side with both adult Caspian and yellow-legged Gulls as well as both Herring Gulls.