While we were not able to apply pre-processing to the eMOP corpus, it is nevertheless an important step in any OCR workflow. At the very least page images need to be binarized—turned into black and white images. There are also options for removing noise, fixing skew, etc. Pre-processing can help to mitigate or remove problems that could affect the quality of your OCR output. However you receive your page images, you should spend some time examining them and, if necessary, pre-processing them for an improved outcome.