Chapter II

Question 1

Basic Principles of Photography

Answer 1

Light
Wavelength

Question 2

within the portion of the electromagnetic spectrum that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400 – 700 nanometers (nm), or 4.00 × 10−7 to 7.00 × 10−7 m, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). This wavelength means a frequency range of roughly 430 – 750
terahertz (THz).

Answer 2

Electromagnetic radiation

Question 3

that makes things visible is classified by the wavelength into a system known as the electromagnetic spectrum.
In 1945, New Mexico City, man for the first time transmitted a substantial quantity of matter into light, heat sound and motion which called energy. If matter sheds its mass and travels with the speed of light, it is called radiation.

Answer 3

Radiant energy

Question 4

a. Light radiated or reflected by the subject must reach the film while all other lights are excluded by placing the film inside a light tight box.
b. The effect of light on the film is not visible in the formation of images of objects. To make it visible, we need or require a chemical processing of the exposed film called development.
c. The visual effect of light on the film after development varies with the quantity or quality of light that reached the emulsion of the film.
(Note: Too much in the amount of light will produce an over exposed photograph.
Too little will produce an underexposed photograph.)

Answer 4

Role of Light in Photography

Question 5

1. Light is a form of energy, and to understand light we begin with the
   electromagnetic spectrum which is basically a grouping of all electromagnetic
   radiation arranged according to the amount of energy contained in the radiation.
2. Visible light is a part of this electromagnetic spectrum that creates the sensation
   of light when it falls on the human eye.
3. The properties of all electromagnetic radiation can be described by three inter –
   related terms.
4. These are wavelength, frequency and energy. Since light is a part of this
   spectrum, it too can be described by these terms.
5. Hence, it is important to understand these terms as a first step towards
   understanding light.

Answer 5

Light: Its Characteristics and Soures

Question 6

Natural Light Source

Answer 6

Moon and Stars
Sunlight

Question 7

Sources of Light

Answer 7

Natural Light Source
Artificial Light Sources

Question 8

Classification According to its Intensity

Answer 8

Bright sunlight/Distinct sun
Hazy Sunlight
Dull Sunlight/Cloudy
Overcast Sky/Cloudy Bright
Heavy Overcast/Cloudy Dull

Question 9

This is the direct sunlight striking the subject. It is the brightest of all, it is highly directional, images taken with distinct sun is characterized by extreme highlights and deep shadows and it provides the highest contrast in a picture

Answer 9

Bright sunlight/Distinct sun

Question 10

It is a hazy sunlight when the sun is covered by thin clouds but still clearly visible and it is illuminating your subject, it produces soft shadows and moderate highlight and contrast is also moderate, while rays are directional.

Answer 10

Hazy Sunlight

Question 11

Objects in open space cast no shadow. It is cloudy when the sun is shining bright but covered with thick moving clouds, other parts of the sky maybe clear, lighting is even throughout and not directional, it does not cast practical shadows on your subject and contrast is relatively fair.

Answer 11

Dull Sunlight/Cloudy

Question 12

Sun is bright but not visible, light is soft and not directional, skies may be covered with stationary clouds and it provides no shadows and low contrast

Answer 12

Overcast Sky/Cloudy Bright

Question 13

This is practically the same as overcast sky but generally darker and light is dull. It provides very poor contrast and static cloud is so thick where one cannot tell the overhead position of the sun.

Answer 13

Heavy Overcast/Cloudy Dull

Question 14

Light sources of this category are man-made and are divided into the
continuous radiation and the short duration. Continuous radiation, those that can give illumination continuously, short Duration and it gives a brief flash of light produced by a burning metallic wire (flash bulb) or an electrical discharge through a gas – filled tube (electronic flash).

Answer 14

Artificial Light Sources

Question 15

this refers to some units are portable battery operated and are easily carried and can meet the rugged and rigorous demand for field work.

Answer 15

UV Lamp

Question 16

This refers to Light Amplification through Simulated Emission of
Radiation. By illuminating certain items with ______, they would fluoresce or could be made to stand out in sharp contrast from their background. This was especially significant in locating dried biological items

Answer 16

LASER

Question 17

This refers to far more expensive alternative to forensic LASER. It uses a variety of band pass filters to provide a high intensity beam of non – coherent light.

Answer 17

Alternative Light Source (ALS)

Question 18

This refers to a wide variety of relatively inexpensive light sources which use filtered white light.

Answer 18

Forensic Light Sources (FLS)

Question 19

Continuous Radiation

Answer 19

Carbon Arc
Incandescent
Photoflood Lamps
Fluorescent Lamps

Question 20

This refers to a pair of carbon rods connected in series with a resistance across direct current.

Answer 20

Carbon Arc

Question 21

This refers to a conducting filament enclosed by a glass bulb heated by the electric current until emits lights.

Answer 21

Incandescent

Question 22

This refers to lamps that can be placed up very high producing deep shadows underneath protruding surfaces, if subject is a person standing, he will appear gloomy and sombre. These can be placed to shine from below giving mysterious and strange effects of frights to observers of the picture.

Answer 22

Photoflood Lamps

Question 23

This refers to illumination in an electric discharge lamp of the mercury – vapor type. The coating fluoresces and sends out light of low brilliance with visible zone.

Answer 23

Fluorescent Lamps

Question 24

Short Duration Radiation

Answer 24

Chemical Flash Lamp
Electronic Flash Lamp

Question 25

This refers to light that produces by the rapid burning of metal wire, foil or primer powders. To produce a rapid and complete burning, the bulb is charged with O2, the lamp flashed once.

Answer 25

Chemical Flash Lamp

Question 26

This is consisting of a slender glass tube filled with a gas (Xenon), a high voltage electrical discharge is passed through coiled tube, causing the gas to glow.

Answer 26

Electronic Flash Lamp

Question 27

Light Angles

Answer 27

Front Lighting
Side Lighting
Back Lighting
Overhead Lighting

Question 28

Distinct sun is used as front lighting when it comes from behind the photographer. It is a common belief that photographs taken at early in the morning or late in the afternoon is better compared to photos taken in any other time of day. The light, when the sun is low, is oftentimes described as magical. Colors are warm, shadows are long, and subject glow with razor sharp clarity.

Answer 28

Front Lighting

Question 29

This type of lighting happens mostly in the morning and afternoonwhen the sunlight hits the subject from either the right or left flank of the photographer. It brings out textures, patterns, and shapes of objects.

Answer 29

Side Lighting

Question 30

This type of lighting happens when the sun strikes the subject from behind or when the sun is directly in front of the photographer. Light coming straight from the back of the subject in portrait produces a bright edged outlined around it. Backlighting also brings out shapes and good profile as well as silhouettes of your subjects.

Answer 30

Back Lighting

Question 31

This normally occurs at noontime where sun is directly above your subject. This angle of lighting is generally not recommended for taking portraits. Strong dark shadows are cast at the subjects’ eyes. However, it can be corrected with a fill – in flash

Answer 31

Overhead Lighting