When most people think about art or the act of painting, they imagine the colors being mixed beforehand on a palette of some sort and then applied to canvas (or other materials) in a continuous brush-like motion. In contrast to this, pointillism is a different style of painting in which images are depicted by a collection of individually-colored dots that the human eye visually combines to “see” a wider range of colors.
Since raster images are really composed of a large number of individually-colored pixels (or dots), the concept of pointillism translates quite naturally to digital graphic design. Just like with digital photos, when pointillism images are viewed from a distance, the eye blends the points of color together to create a picture that seems smooth and continuous with “natural” tones and shaded areas. However, when viewed close up, you can see the actual dots used to create this effect.

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One major difference between hand-painted and computer-generated artwork is that computers are capable of producing hundreds of dots per inch. So, while it may be extremely difficult for the naked eye to detect the individual pixels that make up a photograph without a large zoom factor, it’s usually not so hard to see the points used to create a hand-painted work that incorporates the pointillism technique. In general, as the colored points become smaller and closer in proximity to one another, it becomes harder to distinguish the individual dots.
In graphic design, pointillism can also be used to achieve texture and depth effects in an image by varying the size, shape and spacing of the individual points. Even if the base drawing is more traditional in nature, you can add pointillism to selected areas of the artwork to create the illusion of shadows and other effects that can really bring the drawing to life.