Mirror image

As an optical effect, it results from specular reflection off from surfaces of lustrous materials, especially a mirror or water.

If we first look at an object that is effectively two-dimensional (such as the writing on a card) and then turn the card to face a mirror, the object turns through an angle of 180° and we see a left-right reversal in the mirror.

The concept of reflection can be extended to three-dimensional objects, including the inside parts, even if they are not transparent.

A three-dimensional object is reversed in the direction perpendicular to the mirror surface.

In physics, mirror images are investigated in the subject called geometrical optics.

Thus reflection is a reversal of the coordinate axis perpendicular (normal) to the mirror's surface.

The perception of a left-right reversal is geometrically explained by the fact that a three-dimensional object seen in a mirror is an inside-out version of the actual object, like a glove stripped off the left hand and turned into a right-hand glove, but there is still some confusion about the explanation amongst psychologists.

The psychology of the perceived left-right reversal is discussed in "Much ado about mirrors" by Professor Michael Corballis (see "external links", below).

Reflection in a mirror does result in a change in chirality, more specifically from a right-handed to a left-handed coordinate system (or vice versa).

Some movie theaters also use mirror writing in a Rear Window Captioning System used to assist individuals with hearing impairments in watching films.