Transparency (projection)wikipedia
A transparency, also known variously as a viewfoil, foil, or viewgraph, is a thin sheet of transparent flexible material, typically cellulose acetate, onto which figures can be drawn.
transparenciestransparencysheets of transparent filmtransparency sheetOverhead transparency filmtransparent sheetsacetateProjector transparenciestransparencies (viewgraphs)transparency slides

Overhead projector

overhead projectorOHPtransparencies
These are then placed on an overhead projector for display to an audience. Many overhead projectors are used with a flat-panel LCD which, when used this way, is referred to as a spatial light modulator or SLM.
However some differences are necessitated by the much larger size of the transparencies used (generally the size of a printed page), and the requirement that the transparency be placed face up (and readable to the presenter).

Microsoft PowerPoint

PowerPointPPT.ppt
In recent years, more and more colleges are switching to digital projectors and PowerPoint presentations.
The earliest version of PowerPoint (1987 for Macintosh) could be used to print black and white pages to be photocopied onto sheets of transparent film for projection from overhead projectors, and to print speaker's notes and audience handouts; the next version (1988 for Macintosh, 1990 for Windows) was extended to also produce color 35mm slides by communicating a file over a modem to a Genigraphics imaging center with slides returned by overnight delivery for projection from slide projectors.

Spatial light modulator

spatial light modulatorspatial light modulatorsSLMs
Many overhead projectors are used with a flat-panel LCD which, when used this way, is referred to as a spatial light modulator or SLM.
A simple example is an overhead projector transparency.

Presentation slide

slidesslidepresentation slide
Before the advent of the personal computer, a presentation slide could be a 35 mm slide viewed with a slide projector or a transparency viewed with an overhead projector.

Projection panel

The projection panel sits on the bed of the overhead projector, and acts like a piece of transparency.

Layers (digital image editing)

layerslayerlayered
A layer can be compared to a transparency on which imaging effects or images are applied and placed over or under an image.

Pablo Ortíz Monasterio

In his youth, his parents used to travel frequently and narrate their experiences to their children using transparencies.

Bridgeman Art Library v. Corel Corp.

Bridgeman v. CorelBridgeman Art Library v. Corel Corp
Bridgeman Art Library possessed a large library of photographs of paintings by European masters, as both transparencies and in digital form.

ActivePresentation

Since its inception in 1984 and although purely electronic, PowerPoint has followed the thought process of its physical predecessor, the overhead projector, in which a presenter physically wrote the text and diagrams of the story board sequence on a roll of acetate transparencies.

Presentation program

presentation programpresentation softwarepresentation
As these programs became more common in the late 1980s several companies set up services that would accept the shows on diskette and create slides using a film recorder or print transparencies.

Marker pen

marker penmarkersmarker
Markers may be waterproof, dry-erase, wet-erase (e.g. transparency markers), or permanent.

Printer (computing)

printerprinterscomputer printer
Some printer technologies don't work with certain types of physical media, such as carbon paper or transparencies.

Dry transfer

dry transferrub-on lettering
The decal itself is on a backing material such as paper or plastic sheeting much like a transparency.

Thermofax

thermofax
As copying technology advanced, Thermofax machines were subsequently marketed as a method of producing transparencies (viewgraphs) for overhead projector presentations.

MythBusters

MythbustersDiscovery Channel's MythbustersMythBusters - Collection 4
After some trial and error, the team successfully cast a viable ballistics gel reproduction using a copper-coated circuit board, a picture of the fingerprint printed on acetate, and a photochemical acid etching process.

Page layout

layoutpage layouttemplate
Transparencies for overhead projectors could be printed by some photocopiers.

Alien (film)

AlienAliensAlien: The Director's Cut
The surface as seen from space during the landing sequence was created by painting a globe white, then mixing chemicals and dyes onto transparencies and projecting them onto it. The planetoid was not named in the film, but some drafts of the script gave it the name Acheron after the river which in Greek mythology is described as the "stream of woe"; it is a branch of the river Styx, and forms the border of Hell in Dante's Inferno.

Office 2004 for Mac

Office 20042004 for MacMicrosoft Office for Mac 2004
Microsoft PowerPoint is a popular presentation program used to create slideshows composed of text, graphics, movies and other objects, which can be displayed on-screen and navigated through by the presenter or printed out on transparencies or slides.

Hail to the King (Hillsong London album)

Hail to the KingHail to the King'' (Hillsong London album)
Lins Honeyman of Cross Rhythms wrote that "Whilst this is very much a no frills affair (biographies, powerpoints and the like are not included), the disc does contain a wide variety of sheet music including notation for piano, guitar, drums and bass as well as overhead transparencies and rich text lyric versions of the songs featured on the album proper."

Fingerprint

fingerprintfingerprintingfingerprint sensor
An image editor was then used to improve the contrast and the result printed onto a transparency sheet.

Electrotachyscope

electrotachyscopeelectrical tachyscope
A Geissler tube was used to flash light through the transparencies to provide a weak projection to a single person or small audience through a small window.