1. A method of scoring a printed form having a plurality of preprinted reference marks at known locations and spatial relationships and a preprinted group of bubble targets, each target having a known size and shape at known nominal locations, the bubble targets representing possible responses to a question associated with the form, each target of the target group to be marked or left blank by the subject for the purpose of recording said response, comprising: with a non-dropout scanner, producing a digital virtual form file from the preprinted form, which virtual form defines a virtual layout of the printed form on a virtual coordinate system; non-dropout scanning the marked form to produce a marked form file of gray scale darkness values; comparing the marked form file and the virtual form file to determine the locations and spatial relationships of the reference marks in the marked form file according to the virtual coordinate system; based on the locations and spatial relationships of the reference marks according to the virtual coordinate system, establishing the nominal virtual coordinate location of each target in the marked form file; sampling the gray scale darkness values at each nominal target location and producing an interpreted mark darkness value for each target of the marked form file; interpreting whether the darkness value of the interpreted mark is to be deemed an intentional response; and producing as an output, a scored form file containing a scored value for each target group or target on the marked form page; wherein said production of an interpreted mark darkness value for each target is preceded by filtering out the gray scale contributions of the printed targets at each target location.