HIGHER quality papers and a complex colour scheme may be used for concert tickets in future, to make forgery more difficult. Security coding which allows organisers to distinguish between genuine and fake tickets may also be incorporated, Robert Tsui Pui-lok of the Urban Services Department said yesterday. ''It is too expensive to replace the whole ticketing system, but we can use higher quality paper and add more colours to the tickets to make it more difficult for criminals to make fake tickets,'' he said. ''But however hard we may try to stamp out the fake tickets, criminals can always move a step forward before us. The best way to avoid being cheated is to buy tickets at the official outlets,'' Mr Tsui said. ''As there has been a great leap in printing technology over the past few years, especially the invention of laser printing which makes forgery possible, we cannot be sure fake tickets will never happen again.'' Hundreds of fake tickets were found during a recent concert run by pop star Leon Lai Ming.