CHAPTER 7 HOW LIGHT BECOMES DATA^111
Still other algorithms reach out to pixels located farther away than their nearest neighbors. Different algorithms battling to achieve the
perfect interpolation weight differently the values of different pixels. By applying those weights to different patterns, the array proces-
sor sharpens some areas and blurs others. And, sometimes, the results are not what was expected. In the lighthouse photos here, dif-
ferent algorithms have been applied to the same photo, revealing common artifacts, visual characteristics that are not a natural part
of the photo’s subject. In addition to the blurin the upper-left version, the interpolation used on the copy next to it exhibits tiles. You
might have to study the photo a bit to see the pattern of vertical and horizontal lines added to it. In the bottom-left interpolation, the
watercoloreffect washes out the color in some areas, such as the red life preserver. And shift colorin the bottom-right rendition
produces hues that were never in the original photos. Also, look for loss or gain in detail with different interpolations, as well as
moiré patterns on the building to the left and on the fence, color artifacts on the light house above the building attached to it, and the
good-to-terrible rendering of the lighthouse window.3