When one is "pixilated," according to my dictionary, he's intoxicated, but in a charming, bemused, whimsical, pixyish way. Pixelation can be equally whimsical and bemusing, if applied to the right subjects. Misused, it just turns everything into a bunch of dots. Pixelation happens when similarly colored pixels are clumped together to form larger units, which might be square (pixel-shaped), round, or rounded off by anti-aliasing to whatever form they take. It happens, unasked for, if you're printing a picture at too low a resolution. You end up with large pixels forming jagged shapes that look like they were built out of a child's plastic block set.
When controlled, the effect can be quite interesting. Photoshop includes a set of Pixelate filters that produce different effects all based on the notion of clumping together similar pixels. It's best to apply these effects to simple subjects and to those with strong contrasts, such as the photo of the lighthouse in Figure 16.12.
Figure 16.12 Portland Head Light, Portland, Maine.
Most of the Pixelate filter set looks best if the effect is applied with the Cell Size quite small. Otherwise, the crystals, facets, and so on become so big that the image becomes unrecognizable. In Figure 16.13, I applied the Crystallize filter at a Cell Size of 4. It adds reasonable distortion without destroying the shape of the lighthouse. In Figure 16.14, I pushed the Cell Size up to 50, destroying the picture. You can even set the Cell Size as high as 300, but it turns the entire picture into one or two cells.
Figure 16.13 The Crystallize filter applied.
Figure 16.14 Same filter, overapplied.
Pointillism and Mosaic
As a former art student, it's fun to go back and recall the first time I was introduced to the work of Georges Seurat. It was a revelation (especially after studying some of the "sloppier" French impressionists) to see these dabs of paint all neatly clustered, forming elegant scenes from a distance and forming equally elegant abstract patterns up close. It would be nice if the Pointillism filters did the job as neatly and scientifically as M. Seurat. They don't.
This is, however, one case where the smallest setting doesn't work as well as some of the larger ones. I first tried the picture using 3 pixels as the Dot Size. I got a spotty picture, as I expected, but it looked more like video noise than pointillism. Using a slightly larger Dot Size (8) produced an image a little closer to what I was looking for. But when I tried a much larger size, approximately 25, I ended up with baseballs. Figure 16.15 shows all three effects. Be sure to set your background and foreground colors to something appropriate to the image because Photoshop uses them in creating the dots.
There's a Mosaic setting in the Pixelate effects, but all it does is to make larger pixels out of the smaller ones. The result is the sort of thing used to hide the faces of the people being arrested on all those late-night police shows (see Figure 16.16).
Figure 16.15 From top to bottom, Dot Sizes 3, 8, and 25.
Figure 16.16 Alleged perpetrator, concealed by the Mosaic filter.