Note how "white-winged" the gull looks. The barred undertail coverts are striking and some pale mottling can be seen either through or on the underside of the tail.
A similar shot.
Killer wing detail now, with pretty much perpendicular feather viewing (not edge on). Yes, the secondaries are darker but one web is pale, as are the tips. Also there is darker pigment in p6, p7, and p8 but it is no darker than that elsewhere in the wing.
When viewed edge on from in front the dark pigment in the primaries is most pronounced. This was also true on the standing bird.
This probably best represents what the bird looks like in life in terms of whiteness. Note that the tail has more dark markings visible when fanned, exposing the outer tail feathers - still lots of mottling though. Nice rice cake!
Tertials pattern well shown. Primaries show more tan here than usually visible in life, but p6? (uppermost primary extending past tertials) is very white on both webs. Check out the tail too.
Here no secondary bar is visible. Can see some pink in the bill base.
Wings raised for better tail viewing. Note how the outer part of the tail appears mostly white. Note also striking barred uppertail.
When the primaries aren't disheveled note how all the white tips blend to make the wing tip look very pale. Funny how all those exposed pieces of feathers are the whitest (goes for the tail too!)
Alighting on the lamp post. This bird can look VERY pale!