The method for securing a document comprises the following steps: a step of determining the printing conditions of said document; a step of determining the physical characteristics of cells of at least one form depending on the printing conditions such that the proportion of printed cells showing a printing error which is solely due to printing irregularities is higher than a first predetermined value and lower than a second predetermined value; a step of representing an information by varying the appearance of cells which have said physical characteristics and a step of printing said form by applying said printing conditions, wherein said form is adapted for allowing for the detection of a copy which modifies the appearance of a plurality of said cells.