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Opaque projectors are typically used to project images of book pages, drawings, mineral specimens, leaves, etc. They have been produced and marketed as artists' enlargement tools to allow images to be transferred to surfaces such as prepared canvas, or for lectures and discourses.
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Opaque projectors are still in use for tracing, called tracing projectors. A flat or solid original is projected on a larger sheet of paper onto a wall or easel, where the artist or craftsperson can trace the outline reliably.
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used an opaque projector in demonstrations for huge audiences, for example in the
Philadelphia Opera House which could seat 3500 people. His machine did not use a condenser or reflector, but used an
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At the beginning of the 20th century, projection was split into two classes: "If the light traverses the object, the projection is said to be diascopic, if by reflected light, episcopic."
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is used to focus an image of the material onto a viewing screen. Because they must project the reflected light, opaque projectors require brighter bulbs and larger lenses than
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58:. Care must be taken that the materials are not damaged by the heat generated by the light source. Opaque projectors are not as common as the overhead projector.
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above it. The image from the camera is displayed using a separate projector. The document camera is also called a desktop presenter unit or opaque projector.
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is a device which displays opaque materials by shining a bright lamp onto the object from above. The episcope must be distinguished from the
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demonstrated an opaque projector around 1756. It could project a clear image of opaque images and (small) objects. French scientist
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In the early and middle parts of the 20th century, low-cost opaque projectors were produced and marketed as toys for children.
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Briefe an eine deutsche
Prinzessinn über verschiedene Gegenstände aus der Physik und Philosophie - Zweyter Theil
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is thought to have invented the similar "megascope" in 1780. He used it for his lectures. Around 1872
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In educational settings, the specific role of the opaque projector has been superseded first by the
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the epidiascope, which was capable of projecting images of both opaque and transparent images
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Device that projects image of opaque materials using light, mirrors, prisms, and/or lenses
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332:. Vol. 16 (11th ed.). Cambridge University Press. p. 186 March 2013.
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Swiss mathematician, physicist, astronomer, logician and engineer
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267:"5 Unexpected Items You Can Borrow At Chicago's New Tool Library"
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lamp close to the object in order to project huge clear images.
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Henry Morton's projection as illustrated in François Moigno's
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the episcope, which solely projected images of opaque objects
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The light source in early opaque projectors was often
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Patent #803.385 for one of the earliest epidiascopes
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Two main classes of opaque projectors thus existed:
218:Thomas L. Hankins; Robert J. Silverman (2014).
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50:A system of mirrors, prisms and/or imaging
323:"Lantern § Magic or Optical Lantern"
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293:"Gadgets to Help Make Homemade Crafts"
271:WBEZ, National Public Radio in Chicago
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265:Friedrich, Paula (22 August 2019).
179:for a directory of projector types.
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291:Gregg, David (19 February 2010).
23:An episcope which was used in a
221:Instruments and the Imagination
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207:(in German). pp. 192–196.
121:are most commonly used today.
27:lecture hall in the late 1800s
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69:Small episcope for home use
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346:Episcopes and epidiascopes
177:Projector (disambiguation)
352:Historic Ross Epidiascope
201:Euler, Leonhard (1773).
115:Incandescent light bulbs
329:Encyclopædia Britannica
25:University of Cambridge
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251:L'art des projections
248:'s, François (1872).
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374:Projectors
368:Categories
189:References
111:limelight
297:CBS News
166:See also
41:diascope
37:episcope
74:History
302:11 May
276:11 May
246:Moigno
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183:Telop
147:Types
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