Moiré was a term used by the French to describe the wave patterns on silk imported from Ancient China. Now the term is used to describe interference fringe created by more than two cyclical patterns overlapping. To take a look into the cause behind the formation of moiré pattern, one must understand 'beat phenomenon'.

 Beat phenomenon refers to two waves of slightly different frequencies affecting each other resulting in the bandwidth changing into a certain cycle depending on the difference between the two frequencies. For example, the sound of the Bosingak Bell ring becomes louder and softer repetitively, leaving a trail of sound. More than two slightly different sound waves are created because the area and thickness of the bell do not match perfectly. And these sounds of slightly different frequencies form a certain frequency by offsetting and reinforcing one another. In this process, the bell ring sounds as if it grows louder and softer, until the phenomenon stops when the two frequencies coincide.

 Moiré phenomenon is what happens when the beat phenomenon occurs visually (as light is also a wave). In other words, moiré pattern is an interference fringe that occurs from objects of a certain interval. Also known as 'aliasing', there is the chorma aliasing where the colors change and the luminance aliasing which increases brightness.

 This phenomenon is used for various purposes including to study very small movements of objects or medical imaging, but it is not a good phenomenon to have in photography. Recognizing moiré phenomenon from a dynamic image and looking at a photo of a moiré phenomenon in a static image are not the same.

 Camera technology for photography has applied Optical Low Pass Filter (OLPF) in front of the image sensor to suppress moiré phenomenon by filtering information received by the image sensor and suppressing the interference created by light waves. For this effect, a slightly lower quality of the image was accepted.

 Recently, camera manufacturers have started to advertise their products by emphasizing that they have removed OLPFs, which used to be advertised to eliminate moiré.

 This trend follows a development of image sensor and image processing technologies in the digital camera field. Moiré can be suppressed, and the actual colors of objects can be captured without the use of OLPFs, making OLPFs unnecessary especially as they damage the quality of the image.

 There are more and more cameras with OLPF removed by instead using methods that do not harm the quality of an image, such as camera software that suppresses moiré or irregular arrangement of image sensors.

 It is of course something to welcome that the development of technology lowers limitations in imaging and printing, providing more freedom when it comes to design. Learning about the many limitations in making various design products, other than moiré, will be helpful in improving the level of freedom in design.