An apparatus for preparing a printing plate (130, 1114, 730), the printing plate (130, 1114, 730) comprising a photosensitive polymer activated by exposure to actinic radiation and having a non-printing back side and a printing front side, the front side having a mask embodying image information relating to an image to be printed, the apparatus comprising: a density measurement system comprising: a first radiation source (112,1152,752A,752B) spaced apart from and adjacent the printing plate (130, 1114, 730) and configured to emit a first radiation having a first wavelength or range of wavelengths toward the plate; a densitometer (110, 1150, 750A, 750B) spaced apart from and adjacent the printing plate (130, 1114, 730) in a fixed relationship relative to the first radiation source, the densitometer (110, 1150, 750A, 750B) configured to receive and measure an amount of the first radiation transmitted through or reflected by the printing plate (130, 1114, 730) and the mask; a substrate (160, 1112, 508) configured to receive the printing plate (130, 1114, 730) in a position to receive the first radiation; means for causing relative movement between the printing plate (130, 1114, 730) and the density measurement system; and a density measurement processor (150, 550) configured to process information from the densitometer (110, 1150, 750A, 750B) relating to the amount of measured radiation received over a predetermined region of the printing plate (130, 1114, 730) and to provide an output regarding quality of the mask based upon the processed information. a density measurement system comprising: a first radiation source (112,1152,752A,752B) spaced apart from and adjacent the printing plate (130, 1114, 730) and configured to emit a first radiation having a first wavelength or range of wavelengths toward the plate; a densitometer (110, 1150, 750A, 750B) spaced apart from and adjacent the printing plate (130, 1114, 730) in a fixed relationship relative to the first radiation source, the densitometer (110, 1150, 750A, 750B) configured to receive and measure an amount of the first radiation transmitted through or reflected by the printing plate (130, 1114, 730) and the mask; a first radiation source (112,1152,752A,752B) spaced apart from and adjacent the printing plate (130, 1114, 730) and configured to emit a first radiation having a first wavelength or range of wavelengths toward the plate; a densitometer (110, 1150, 750A, 750B) spaced apart from and adjacent the printing plate (130, 1114, 730) in a fixed relationship relative to the first radiation source, the densitometer (110, 1150, 750A, 750B) configured to receive and measure an amount of the first radiation transmitted through or reflected by the printing plate (130, 1114, 730) and the mask; a substrate (160, 1112, 508) configured to receive the printing plate (130, 1114, 730) in a position to receive the first radiation; means for causing relative movement between the printing plate (130, 1114, 730) and the density measurement system; and a density measurement processor (150, 550) configured to process information from the densitometer (110, 1150, 750A, 750B) relating to the amount of measured radiation received over a predetermined region of the printing plate (130, 1114, 730) and to provide an output regarding quality of the mask based upon the processed information.