time, we chose a picture part—in 100% zoom—which clearly
depicts today's foe, the blue-purple color defect. Particularly
problematic locations have been marked by red arrows. You
can also see that, as opposed to regular chromatic aberration,
the phenomenon is mainly represented by a single color.
There are no opposite-color borders along the other sides
of high-contrast edges. This way, the defect only concerns
a single color channel—the blue one. By shifting the blue
color channel in the opposite direction, we are likely to
reduce the annoying discolored edges.
starting off, observe the width of the edges and the direction
of the color runs, since these will be crucial for shifting
the color channel. In this example, the defect drags 3 to
4 pixels slightly to the left, so we'll need a little offset
downwards and to the right.