1. A method of determining the center of focus in a lithography device utilizing latent image analysis, comprising the steps of providing a substrate comprising a plurality of latent image diffraction gratings made utilizing the lithography device, the plurality of diffraction gratings comprising different known focus settings; determining a diffraction signature for at least three of the plurality of latent image diffraction gratings by means of a radiation source-based tool; measuring the differences between the diffraction signatures between adjacent focus setting latent image diffraction gratings; and determining the center of focus as the focus setting wherein there is a minimal difference between the diffraction signatures of adjacent focus setting latent image diffraction gratings.