The idea of optical character recognition (OCR), in other words the “reading” of documents by other than human means, arose as a practical proposition during the Second World War. Wartime experience of using computers in the United States had revealed the contrasts in speeds between the transcription of documents to be processed (at that time the punching of cards or tape by operatives working from original documents) and the central processing within the computer itself. Visual output was also slower than central processing but was much speeded up by the introduction of line printers and later of xerography. This “paired” case study, part of a project sponsored by the Science Research Council to examine patterns of success and failure in industrial innovation, is confined to two attempts to innovate in the field of OCR. There were others, one or two of which were contemporary, most of which have followed, have a much more recent history and may be thought to have overtaken, in terms of market penetration, the innovation here designated a commercial success. The point of this study when it was undertaken was to extract data about the two innovations that would be suitable for general analysis by a computer programme designed to search out significant groups of explanatory factors so that the characteristics associated with innovative success might be recognised as typical within an industry, or perhaps generally. This study belongs to one of two groups, the instrument industry, the other group investigated being chemical manufacturing.