Described herein are devices and methods related to fabrication of organic electroluminescent devices and related components. In certain embodiments, devices and methods for fabricating OLED panels on substrates with non-uniform reflection or un-even surfaces require that the non-uniform features are arranged in a way such that they are not presented in the region where photolithography features are needed. In certain embodiments, where precision processing such as photolithography features are needed, the substrate is designed to be flat.