A slideshow is a series of single images, or slides, displayed in order. Traditionally, a slideshow was a literal show of slide reversal film, usually operated via carousel, or an overhead projector. In modern times, a slideshow is more likely to be operated by a computer, with prepared slide images that might consist of text and images created in a software application such as Powerpoint.
Early slideshows were operated using a slide projector, a special device intended especially for the slideshow. A slide projector has some sort of high-powered light bulb, usually kept cool with a fan, some sort of holder for the slide itself, a condensing lens to focus the light on the slide, and a focusing lens to make the image appear in focus at different distances. These slide projectors had a simple slot for the slide to be fitted into, and after each slide it would have to be removed so the next could be shown. The carousel slide system changed this, by allowing many slides to be placed into a single carousel, which could then be advanced with the click of a single button. This led to an explosion in the popularity of the slideshow, both for home and business purposes in the 1950s and 1960s.
The slideshow is a popular device for showing vacation trips, and especially during the 1950s and 1960s it was a common occurrence after a trip to return home and invite friends over to see photos of the trip. A carousel slide projector allowed for an entire trip’s worth of photos to be cued up, and friends could watch as photo after photo was blown up larger than life on to a projector screen. In modern times it is more common for people to create home movies, or digital photo albums which can be sent to friends online, rather than engaging in a literal slideshow.
In business, too, the slideshow has long been popular as a way of conveying information to groups of people. Even when slides had to be individually prepared, the ability to merge images and text easily and show it in business meetings or auditoriums made the slideshow an ideal way to communicate with clients or business partners. With the proliferation of the personal computer, business slideshows have become even more commonplace, as software makes it easy to put together a comprehensive slideshow in very little time, even integrating multimedia like videos and sounds to make a more dynamic experience.
The term slideshow is also used in a more general sense to refer to any sequential display of images. Many photo viewing programs, for example, feature a slideshow feature, where a range of photos can be viewed in order, with brief pauses between each, and often accompanying transition effects and music. This mimics the earlier consumer slideshows of the 1950s through 1980s. A type of screensaver is also known as a slideshow, where images are displayed at random or in a set order when the computer remains dormant for a period of time.