Method for verification of the alignment of at least one print head (1a, 10a, 1b, 10b, 1c, 1d) installed in a printing machine, by linear adjustment of at least one group of dots shown in an image produced by digitisation of a pattern comprising a plurality of printed drops, characterised in that each drop has a plurality of dots, each dot having a uniform colour in conformity with a colorimetric data base saved in a memory zone of a computer system implementing the method and comprising at least one memory space, means for acquisition, for recording and for processing of the data, the method comprising: a. a step for detection of the colour of the dots by the processing means, followed by the allocation by the processing means of spatial coordinates and colorimetric coordinates to each dot of a digital image of a pattern recorded in memory, these coordinates being associated respectively with a spatial mark relating to the image and a colorimetric table recorded in a memory space of the computer system, b. a step for creation, by the processing means, of at least one list of dots having the same colorimetric coordinates, the data relating to at least this list being recorded in memory by the means for recording the data, c. a step for creation, by the processing means, of at least one group of dots from a same list of dots having the same colorimetric coordinates and each dot of which belonging to said group has to be located a distance less than a distance d/2 from a dot of another group, the distance d recorded in memory corresponding to the minimum distance between two groups of dots, d. a step for filtering and elimination of the groups the number of dots of which is less than a limit value recorded in a memory zone of the computer system, e. a step for vectorisation, by the processing means, of at least one group of dots, followed by the recording in memory by the recording means of the coordinates of at least one corresponding vector, f. a step for association, via the processing means, of each vector with the corresponding print head (1a, 10a, 1b, 10b, 1c, 1d), a data base associating each print head (1a, 10a, 1b, 10b, 1c, 1d) with a colorimetric coordinate being recorded in memory, g. a step for comparison with the aid of the processing means of the coordinates of the vectors with the coordinates of the respective optimum vectors recorded in memory and characterising an optimum alignment of the heads (1a, 10a, 1b, 10b, 1c, 1d). a. a step for detection of the colour of the dots by the processing means, followed by the allocation by the processing means of spatial coordinates and colorimetric coordinates to each dot of a digital image of a pattern recorded in memory, these coordinates being associated respectively with a spatial mark relating to the image and a colorimetric table recorded in a memory space of the computer system, b. a step for creation, by the processing means, of at least one list of dots having the same colorimetric coordinates, the data relating to at least this list being recorded in memory by the means for recording the data, c. a step for creation, by the processing means, of at least one group of dots from a same list of dots having the same colorimetric coordinates and each dot of which belonging to said group has to be located a distance less than a distance d/2 from a dot of another group, the distance d recorded in memory corresponding to the minimum distance between two groups of dots, d. a step for filtering and elimination of the groups the number of dots of which is less than a limit value recorded in a memory zone of the computer system, e. a step for vectorisation, by the processing means, of at least one group of dots, followed by the recording in memory by the recording means of the coordinates of at least one corresponding vector, f. a step for association, via the processing means, of each vector with the corresponding print head (1a, 10a, 1b, 10b, 1c, 1d), a data base associating each print head (1a, 10a, 1b, 10b, 1c, 1d) with a colorimetric coordinate being recorded in memory, g. a step for comparison with the aid of the processing means of the coordinates of the vectors with the coordinates of the respective optimum vectors recorded in memory and characterising an optimum alignment of the heads (1a, 10a, 1b, 10b, 1c, 1d).