Hi Anne A system similar to those already described is used at Tate: loans-in and acquisition candidates are given an 'X' pre-fixed object number and assigned to their own departments ('Acquisition Candidates' and 'Exhibition and Display Loans In'). When an acquisition candidate is accessioned it's given a new accession number, with the old, 'X' number, retained as an alternate number and the department is changed to 'Main Collection'. Jon Thristan Tate