diorama, three-dimensional exhibit, often miniature in scale, frequently housed in a cubicle and viewed through an aperture. It usually consists of a flat or curved back cloth on which a scenic painting or photograph is mounted. Flat or solid objects are placed in front of the back cloth, and coloured transparent gauze or plastic drop curtains are used to heighten the three-dimensional effect. A considerable improvement in perspective is achieved by the addition of stage borders or wings. The rigorous application of the laws of perspective is essential to the success of the exhibit. The skillful use of lighting also heightens the effect and was deployed memorably in shows such as the Eidophusikon of Philip James de Loutherbourg during the 18th century.

True dioramas, used for peep shows and the like, probably originated before the 19th century; but credit for the development of the diorama is usually given to Louis-Jacques-Mandé Daguerre, a French scenic painter, physicist, and inventor of the daguerreotype, who, with his coworker Charles-Marie Bouton, in 1822 opened an exhibition in Paris that he called the Diorama. Daguerre’s techniques survive in contemporary dioramas, which are often employed in museums and may depict any subject on any scale.

The word diorama may also refer to a length of painted canvas depicting a scene or landscape. Such a canvas, sometimes called a rolled panorama, is slowly rolled across a stage, either horizontally or vertically, to depict movement through space. In the 19th century these displays either accompanied lectures (usually about travel or current events) or created the illusion of motion as an accompaniment to dramas. The American artist John Banvard’s depiction of a trip along the Mississippi River was 1,200 feet (370 metres) in length. (See also cyclorama.)