This document discusses opaque materials and opaque projectors. It defines opaque materials as materials that do not allow light to pass through them and provides examples such as stones, wood, and metal. It then discusses the characteristics of opaque materials such as having color depending on absorbed light and casting shadows. The document also discusses opaque projectors, defining them as devices that project opaque materials using reflected light. It provides types of opaque projectors and their characteristics, advantages, disadvantages, applications, and precautions for handling them.

1. ELECTRICAL DEPARTMENT
COURSE NAME: EDUCATION TECHNOLOGY
UNIT CODE: ED7104
LECTURER: MR. MUTHIANI
GROUP 1
No NAME ADMISSION
NUMBER
SIGNATURE
1 GITAHI TIMOTHY
KABUGI
2022EE150021
2 MWANGI MIRIAM
WANGARI
2022EE150394
3 ALPHONCE ONYANGO
OKIYA
2022EE150179
4 RUFUS MUTWIRI
KARIUKI
2022EE150275
5 KENNEDY BUKACHI
OBIERO
2022EE150184

2. OPAQUE MATERIALS
 These are materials that do not allow light to pass through them.
 They are projected on a screen using opaque projectors.
 Most of the light is either reflected by the object or absorbed and converted to thermal
energy
TYPES/EXAMPLES
They include the following
 Stones,
 Monuments and Sculptures
 , Tables
 Metals
 Concrete
 Wood
 Metal
 Paper board
 Cell phone
 Chair
 Car
 Matters
 Monuments and sculptures
CHARACTERISTICS OF OPAQUE MATERIALS
1. The color of the material depends on the light it absorbs.
2. They have a shadow.
3. The ability to transmit lights varies from object to object, the amount of light that can
pass through the object depends on the density of molecule,
it is impossible for light to penetrate them.
4. Opaque objects are those that do not allow light to pass itself, when light illuminates no
light pass through it.
5. Some opaque object absorbs the light that shines on them however some of them have
little of light get reflected back.
6. Most objects can be described with that objective, because when ray of light illuminate
them none is visible through itself.
7. They have shadow since no light pass through them

3. 8. An object located on the other side of this material is not visible at all.
9. Most of opaque materials the colour of material depends on the light it absorbs
ADVANTAGES
1. They don’t allow the light through hence appreciates privacy.
2. They provide shade.
3. Most of the opaque materials are very hard.
4. The opaque materials are usually durable.
5. Can be used for construction works.
DISADVANTAGES
1. Seems to be very expensive.
2. They cannot be used as material in construction of greenhouse.
APPLICATIONS
1. Used in the Construction materials like wood.
2. Used for shading.
3. They can be used for reflectors.
4.
OPAQUE PROJECTORS
This refers to a device that projects opaque materials by means of reflected light. It can also be
defined as a device that projects opaque materials in 2 dimension with the help of reflected rays.
A system mirror, prism and or imaging lenses is used to focus an image of the material onto a
viewing screen because they must project the reflected light, opaque projectors requires brighter
bulbs and larger lenses than overhead projectors.
Opaque projector are typically used to project images of book pages, drawings, mineral
specimens, leaves etc.
They have been produced and marked as artist enlargement tools to allow images to be
transferred to surfaces such as prepared canvas, or for lectures and discourses.
TYPES OF OPAQUE PROJECTORS
1. Episcope Projectors
An episcope is an optical device for projecting flat opaque images, like postcards, prints,
photograph, pages of books, but also three- dimensional objects like coins, insects and
leaves, on to a screen.

4. 2. Epidiascope Projectors
– It combines the ability to view transparent and opaque objects into one device.
An epidiascope is a device used to project images of both opaque and transparent images,
typically used to project images of books pages, drawings, minerals specimens, leaves, etc.
An example of a large epidiascope.
This device was used to show mounted glass slides in lectures and colloquia.
CHARACTERISTICS OF OPAQUE PROJECTORS
 Equipment designed for the direct projection of object: original products, books and
kinds of documents.
 Suitable for transparencies projection.
 Halogen lamps 4 110v/300w.
 Projection distance: 1.30- 3m.
 Extension : from 3 to 8 times.
 Work surface 285×285mm
 Weight: 12kg
 You can also reduce images up to 80% over the original
 It includes the super prism lens, which represents a remarkable improvement in the
quality of the reproduction with respect to the models.
 Double cooling channel with a circuit thermal overload sifting system to protect the copy
from overheating
 The projected image can be easily taken and can be colored as desired
PRECAUTIONS WHEN HANDLING OPAQUE PROJECTORS
1. Should be handled carefully.
2. Must be protected from damage.
3. Must be protected from moisture.
4. Must be free from dust.
5. Must be switched off when not in use.
6. Should preferably be kept in a cool room.
ADVANTAGES OF OPAQUE PROJECTORS
1. Graphic aids are projected with magnification
2. Flat specimen can be projected.

5. 3. It is possible to trace enlarged images.
4. Can be conveniently seen by a large audience.
5. Teaching materials of different sizes can be used.
DISADVANTAGES OF OPAQUE PROJECTORS
1. Darkness is mandatory.
2. Difficult to maintain.
3. Inconvenient since electricity is required.
4. Bulky and unavailable.
APPLICATIONS OF OPAQUE PROJECTORS
1. Use in projection of graphic aids.
2. Used in tracing and enlarging images.