..it [the large painting 'Bathers at Asnieres', by Georges Seurat was painted in great flat strokes, brushed one over the other, fed by a palette com… - Paul Signac

Of the three primary colors, the three binary ones are formed. If you add to one of these the primary tone that is its opposite, it cancels it out. This means that you produce the required half-tone. Therefore, adding black is not adding a half-tone, it is soiling the tone whose true half-tone resides in this opposite me have just described. Hence the green shadows found in red. The heads of the two little peasants. The yellow one had purple shadows; the redder and more sanguine one had green ones.

The Pointillist chooses a means of expression by which he applies colour on a canvas in small dots rather than spreading it flat.

Divisionism is a complex system of harmony, an aesthetic rather than a technique.
The point is only a means.
To divide is to seek the power and harmony of color, through representing colored light by pure elements, and through employing the optical mixture of these pure elements, separated and proportioned according to the essential laws of contrast and graduation.