Abstract: An image processing method operates on a coloured digitised image in a computer (2) to derive the image in abstract computer representation. Colour is used to pre-classify symbols and other features of the digital image in order to simplify subsequent character recognition steps. By preparing the image in accordance with rules such that a unique colour is used for all features of a defined set, and by storing those features in the computer in computer representation in corresponding sets, once a match has been made between a graphic feature and a stored feature, then the colour of that graphic feature is made unique to the set of stored features containing the matched feature. The remaining graphic features of that colour then need to be compared only with the stored features in the same set, rather than with all the stored features (of all the sets), thus significantly reducing the character recognition processing that is required to effect matching.