it is better to say reportage on a subject or reportage about?
For instance: a reportage about september 11th or reportage on september 11th
Another thing: 'reportage' is uncountable (except, possibly , when referring to the genre of a piece of work: 'The winner of first prize was a reportage on life in the barrio' (I'm really not sure about this; I've met it a few times though.)).
And another thing; the pronunciation reflects the French - /ɑ:ʒ/ not /ɪʤ/.