Moiré pattern is an unfortunate artifact of digital photography and other imaging techniques. It appears as a series of interference patterns that appear over your image. In this article, we’ll take a look at why moire occurs and how you can avoid it or remove it from your photos.
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What Is Moire?
Moiré is an optical phenomenon that occurs when two repeating patterns (or one repeating pattern and another image) overlap and interfere with each other. The interference creates a pattern of light and dark lines that can be seen in the overlapping areas. Moire patterns are more commonly seen in fabric, but they can also appear in photographs when there are high contrast, repetitive patterns that are overlaid on each other.
Moire Patterns
One of the most common types of moire pattern is seen on fabrics like those found in clothing or curtains. These fabrics have distinctive horizontal or vertical lines that create an optical illusion when viewed from afar. When these fabrics are photographed, they can produce moiré patterns because their repeating lines will interfere with each other creating a visible grid effect.
Moiré pattern is a type of interference pattern caused by the overlap of two or more grids. It’s most often seen in images captured with digital cameras and is most commonly caused by the grid of pixels that make up the image sensor.
The term moiré is derived from the French word “moire”, meaning a watered silk fabric with a wavy surface. The moiré effect is similar to the appearance of this fabric under certain lighting conditions, which causes regular patterns to appear to move or change shape (see below).
The same principle applies to digital photography, except that instead of light reflecting off the surface of a physical object, it’s digital light being reflected off an electronic device (such as your camera). The interference pattern results from two different repeating patterns overlapping each other in such a way that they create new shapes at their intersections.
Moiré can be caused by any repeating pattern that interferes with another one, but it’s most commonly seen in photos because images are made up of rows and columns of pixels that repeat over and over again like a grid. In addition, digital cameras have an array of tiny lenses called “microlenses” that form another kind of grid on top of each pixel.
How to Spot, Avoid and Remove Moiré in Photos
Moiré can be caused by a number of things, including:
- Dense grids or textures on clothing or furniture, especially if they’re moving (for example, people wearing plaids)
- Patterned fabrics like corduroy or denim
- Fine stitching on clothing, especially when it’s moving (like when someone’s walking).
- In other words, if you have an image with any kind of repeating pattern (for example, the squares on this page), and you take a photo of that pattern with a camera that has a sensor that isn’t 100% fine-pitched (like most of today’s digital cameras), then you might see some moiré in your photos.
To avoid moiré:
- Use a lower resolution camera (8 megapixels or less).
- Shoot at wider angles (as opposed to zooming in on your subject).
- Use an anti-aliasing filter on your lens (this will slightly soften the image).
- The best way to avoid moiré is to avoid photographing subjects that have very obvious repeating patterns. If you’re shooting a cityscape, for example, it’s best not to include buildings with brick or concrete facades because they will likely create a moiré pattern in your photo.