SLIDE
PROJECTOR
Submitted to
Dr. Sukhwinder Madam
Lecturer
Submitted by
Parisha Rai
M.Sc Nursing 1st year
N.I.N.E
P.G.I.M.E.R
Definition
A projector is an optical instrument that projects an enlarged image onto a screen.
A slide is a small piece of transparent material on which a single pictorial
image/scene/graphic image has been photographed or reproduced otherwise.
So a slide projector is an opto-mechanical device to show photographic slides. Projectors are
sometimes called "front projectors" or "two-piece projection systems" in reference to the fact
that a projector is typically used with a separate screen that is either mounted on a wall or
hung from a ceiling. It was common in the 1950s to the 1970′s as an entertainment.
History
The Magic Lantern was the forerunner of the modern slide projector. First used by 17th
century scientists. However, researchers do not know who invented the first one. In 1676, a
type of Magic Lantern called the Sturm Lantern was invented and it may have been one of
the first.
Manufacture of Lantern Slides: The first lantern slide producers made their slides using
albumen-coated plates and, after a short period, switched to wet-collodion plates. The
introduction of dry plate processes, as well as mass-produced lantern slide kits, made the
slides easier for amateur photographers to produce and also made them more accessible to
schools and universities.
Early Electric Slide Projectors: Electric slide projectors gradually replaced Magic Lanterns in
the early 20th century. The Kodaslide projector model, introduced in 1939, displayed
individual color Kodachrome film slides placed manually into the projector, one by one
Slide Projectors Discontinued: As digital photography usurped film in the 1990s and 2000s,
slide projectors fell out of common use. Kodak discontinued the production of its projectors
in 2004.
Parts of slide projector
Electric incandescent light bulb or other light source (usually fan-cooled): A slide projector
uses an intensely hot, high-powered halogen lamp. They are designed to last for at least 80
hours of use in normal circumstances.
Reflector and "condensing" lens to direct the light to the slide: There is a flat piece of heat-
absorbing glass placed between the lens and the slide to help keep the slide from being
damaged-the glass transmitting the visible wavelengths of light while absorbing infrared.
Slide holder
Focusing lens
The Fan Assembly: An electric motor drives a small fan inside of the slide projector which
blows air across the bulb in order to cool it. There are vents on the outside of the slide
projector, and from these both the intake of air and exhaust of air occur.
The Slide Tray: A slide is placed in a tray that attaches to the slide projector. This tray can be
rectangular in shape, moving the slide to be viewed from front to back, or circular, moving
the slide to be viewed in an arc.
The Slide: A slide is a small piece of transparent material on which a single pictorial
image/scene/graphic image has been photographed or reproduced otherwise. Molded slides
range in size from 2 by 2 or 4.5 by 4 inches. Slides can be made from photograph and
pictures taken by teachers and students when they go on fieldtrips for historical,
geographical, literary or scientific excursion. The 35mm slide frame has a unique shape that
sets it apart from other presentation media. The 2:3 ratio (height: width) appears wider when
projected than overhead transparencies and video images. If the slides are not created in the
proper ratio, they usually end up with partially filled slides, wasting valuable space.
Types of projector
Carousel slide projectors
The Carousel projector is representative of the various types of slide projectors in use.
This projector accepts any slide mount whether it is glass, cardboard, metal or plastic as
long as the outer dimensions do not exceed 2 inch by 2 inch (50mm by 50mm). The
standard slide tray furnished with the projector accepts 80 slides which mount up to 1/10
of an inch (2.5mm) thickness and the optional universal slide tray accepts slides up to 1/8
of an inch (3mm) thickness. Slide identification numbers are moulded on the tray. A
locking ring fits on top of the tray to keep the slides from spilling if the tray is inverted.
The carrying case provides a means of carrying and storing the projector.
Straight-tray slide projectors
Dual slide projectors
Overhead projectors
Single slide projectors (manual form)
Viewer slide projectors
Slide Cube projectors
Stereo slide projectors project two slides simultaneously with different polarizations,
making slides appear as three-dimensional to viewers wearing polarizing glasses
Large Format Slide Projector for use on stages, at large events, or for architectural and
advertising installations where high light output is needed
How to Use Slide Projectors
Instructions
1. Arrange the slides in a carousel in order of appearance. Place each slide upside down
with the emulsion side toward the screen. Choose the images carefully.
2. Check the focus. Most newer projectors are automatic focus, but there might be a
projector with a manual focus or some combination of the two. If the projector does
not have a zoom lens, then it may be advantageous to set the machine on a cart with
wheels.
3. Test the remote control for the projector. This allows the speaker, to stand in front of
the audience and advance the pictures by the push of a button. Usually the remote
control is connected to the projector by a small wire, and it has a button for both
forward and reverse.
Tips & Warnings
1. Do not use the best slides in a projector with an ordinary light bulb as a light source.
We need to have duplicates made for the presentation, because the heat of the lamp
softens the emulsion layer of the film, and when dust hits the soft surface, it becomes
embedded. Another option is to shoot multiple pictures of the subject matter and then
delegate one of the identical pictures to be used solely as a projected image. (This
problem does not occur in a digital projector.) When the presentation is over, the fan
should be left running for several minutes after the lamp is turned off. This helps the
bulb of the slide projector cool down gradually otherwise hours of use of the bulb can
be lost.
2. A good presenter who is using a slide projector can use the projector to focus the
audience's attention on himself or on the images. A blank slide can then be thrown in
so that the audience is not distracted and refocuses their attention on the presenter.
Advantages:
1. 35mm slides are small, inexpensive, and easy to project
2. Help in retention of material taught in the minds of the pupils
3. Attract attention
4. Arouse interest
5. Test student understanding
6. Review instructions
7. Facilitate student teacher participation
8. Better quality photos or images
9. Space saving
10. Easy to install
11. Their small size makes them more manageable and portable than overhead
transparencies. When kept in their trays, they are easy to handle and relatively safe
from most mishaps. A case containing a slide projector and a tray of up to 140
slides can easily fit under an airplane seat.
Disadvantages/Limitations:
Dark room often required: Most slide projection setups require at least a partially
darkened room for maximum readability but the darkness diminishes eye contact and
prohibits the presenter from being able to monitor the audience’s reaction, and
contributes to audience drowsiness.
A speaker cannot write on or directly affect a projected slide for emphasis (except for
the limited use of a pointer).
Because of the imaging and processing requirements of slides, last-minute changes
(less than 4 hours) can be impossible.
A carousel of slides is bulky for travel.
Slides can jam. The remote can break. The bulb can burn out.
Slides have to be mounted in trays before viewed efficiently in sequence.
o Mounting out-of-order, upside-down or backwards is a common
occurrence.
o The slides can easily fall out of the tray before putting them on the
projector, causing disturbance in the classroom presentation.
Maintenance required: All projectors operate on lamps that need to be replaced
periodically. The frequency of lamp replacement depends on the model and on our
usage, but many projector users replace lamps every two to three years. In addition to
lamp replacement, most projectors have air filters that need to be cleaned or replaced
every couple of months. Failure to keep filters clean can reduce lamp life and increase
the chances of dust getting into the unit and creating fuzzy spots on the projected
image.
Rainbow artifacts: Some users of projectors color separation artifacts, commonly
known as rainbows, or rainbow artifacts. This is an unfortunate side-effect of the
spinning color wheel in the light engine of a projector. Most people are not sensitive
to this phenomenon, but those who are can experience it as anything from a minor
distraction to a severe flaw that makes the projector unwatchable. In addition to being
visually distracting, the effect is also reported to cause headaches and eyestrain.
Reference
1. Lakenster T. Setting up Community health programme: a practical manual for use in
developing countries. Macmillan India Ltd. Publishers; 1994. p. 124-125.
2. Pramilaa R. Nursing communication and educational technology. Jaypee Publishers;
2001. p. 370-371.
3. Neeraja K.P. Textbook of Nursing Education. Jaypee Publishers; 2005 reprint. p. 223.
4. Chanda E. Introduction to Nursing Education. PeeVee Publishers; 2011. p. 145-146.
5. http://www.ehow.com/how_4813099_use-slide projectors.html#ixzz2Zyyh8DPI
6. http://www.ehow.com/how_4813099_use-slide-projectors.html#ixzz2ZyyqyTTW
