Over Sharpening Can Create Moiré Patterns

Notice the funny looking pattern in the blinds on yesterday’s photo I posted. This is called a moiré pattern and it’s caused by too much sharpening for the particular image. The sharpening process creates a pattern in the image that can combine with existing patterns in the image to create a moiré pattern. See www.mathematik.com/Moire for a great example. Patterns like these are frequent occurrences in interiors and exteriors. The horizontal pattern of on exterior home siding is creates this situation. Notice the similar moiré pattern in my Apr 27 post in the siding of the yellow house.

All I did to the image above to eliminate the moiré pattern was to reduce that amount of the of sharpening.