The invention relates to method for generating a folding instruction for folding a stack of sheets into a document, the method comprising the steps of for each sheet of the stack of sheets, receiving a folding action on the sheet defined by a fold type and an orientation relative to an observer, the fold type selected out of a mountain fold right, a mountain fold left, a mountain fold bottom, a mountain fold top, a valley fold right, a valley fold left, a valley fold bottom and a valley fold top, generating a function which has the folding action and the sheet as input and an ordered list of new sheets with an orientation relative to the observer of each new sheet of the list of new sheets as output, repeatedly applying the previous steps to each sheet of the at least one list of new sheets until the sheets in the last applied previous steps form the document, and generating a folding instruction comprising a concatenation of the at least one generated function on the stack of sheets, the folding instruction intended to be transmitted to a folding device for folding the stack of sheets into the document.
The invention also relates to a folding device and a document processing system for applying the method according to the invention.