IS THIS A MEW GULL OR COMMON GULL?
note: photo is said to be overexposed

Here is a short description, mainly based on the original slide, by Laurent Raty:

BILL COLOR: Yellow with a very faint dark subterminal band (unobvious on the scan but can be seen on the original slide) - not the most frequent color for _canus_ in winter, but certainly possible; may fit both.
LEG COLOR: Dirty yellow - may fit both.
IRIS/ORB RING: Was not seen in the field and can not be seen from picture either.
HEAD : Seems lightly streaked on crown - could better fit _canus_, but picture is slightly overexposed, which may cause head to appear whiter than it was in reality.
UNDERPARTS: White - not discriminant.
PRIMARIES: A-spot diminish in size: A5 largest, A8 very tiny (almost invisible on the scan), none on P9-10; extensive black and large mirrors on P9-10; no mirror on P8; large white tongues on P5-8; thin black band on P5 - apparently, excludes _canus_ and fits _brachyrhynchus_ to the perfection... (description based on *left* wing - I am not sure this pattern is mirrored on right wing, which is less well visible).
SECONDARIES: Adult gray w/ broad white trailing edge - not discriminant.
TERTIALS: Adult gray w/ large white crescent, about bill length - not discriminant.
GREATER COVERTS: Adult gray - not discriminant.
LESSER & MED COVERTS: Adult gray - not discriminant.
SCAPULARS: Adult gray, scapular crescents not visible on picture - not discriminant.
BACK: Adult gray is med gray, clearly darker than _argenteus_ Herring; no direct comparison with other _canus_ - may fit both.
RUMP: White - not discriminant.
TAIL: White - not discriminant.