1. A method of optimally adjusting an imaging process parameter in the preparation of a lithographic printing surface, said method comprising the steps of: a) imaging a test pattern on a lithographic printing precursor to create by means of said imaging an imaged lithographic printing precursor using at least one write radiation beam; b) converting said imaged lithographic printing precursor into said lithographic printing surface; c) reading back said test pattern from said lithographic printing surface using a radiation source impinging on said test pattern and a radiation detector disposed to measure the reflected radiation from said test pattern and d) analysing said reflected radiation to determine optimal adjustment for said imaging process parameter.