POTHOGRAHY. forensic reviewer future RC..

MARK LESTER MENDOZA-FLORES, R.C
Instructor / Lecturer
MARK LESTER FLORES 2012

Brief history of Police
Photography
The word “photography” was
coined by Sir John Herschel,
who first used the term in 1839,
the year photographic process
became public.

Light Projection through a Pin
hole
Light projection

The Pin – Hole Camera
Pin hole

Pinhole Camera
A simple camera can be built by
making a pinhole in a box. Light
passes through the hole and
forms an inverted, backwards
image of the subject on the back
of the box. Artists of the
Renaissance used a similar
device, called the camera
obscura, as an aid to drawing. The
earliest camera obscura was a
small room, on the back wall of
which the artist could trace the
projected scene.

The Camera Obscura
 Giovanni Battista Della Porta – was the
reputed inventor in 1569 of the
“Camera Obscura”. This invention was
the logical outcome of the discovery of
the possibility of projecting an image
through a minute hole.

The Camera Obscura
 Means “dark room”. A darkened
enclosure in which images of outside
objects are projected through a small
aperture or lens onto a facing
surface.

Camera obscura

CAMERA OBSCURA

Modern camera and the Camera Obscura

 Joseph Nicephore
Niecepce – in 1827
obtain the first fixed
image.
 Created the first
surviving permanent
photograph by using
a camera obscura, a
precursor of the
camera. He died in
1833 having been
unable to perfect the
technology.
PROPONENTS OF PHOTOGRAPHY
Joseph Nicephore Niecepce

 Louis- Jacques-Mande
Daguerre – a French
artist and chemist,
recognized for his
invention of
Daguerreotype process
of photography.
Louis- Jacques-Mande Daguerre

Daguerreotype – were the
forerunners of our modern film.
- It was made of a copper plate
coated with silver and exposed to
iodine vapor before it was exposed
to light.
- To create the image on the plate, it
must be exposed to light for about
15 minutes.

 Henry Fox Talbot – in 1834 created
permanent (negative) images.
- He use paper, soaked in silver chloride and
fixed with a salt solution.
- He the one created positive images by
contact printing onto another sheet of paper.
Calotype – process in the year 1840.
- in this process, Talbot coated paper sheets
with silver chloride to create an intermediate
negative image.

Brief History of Forensic
Photography
 Forensic Photography
- sometimes referred to as police
photography, forensic imaging or crime
- is the art or science of documenting
photographically a crime scene and
evidence for laboratory examination
and analysis for purposes of court trial.

Police Photography- is an art or
science that deals with the study of
the principles of photography, the
preparation of photographic evidence
and its application to police work.
Scene photography - is the art of
producing an accurate reproduction f
a crime scene or an accident using
photography for the benefit of a court
or to aid in an investigation.

Photograph - is an image created by light
falling on a light-sensitive surface usually
photographic film or electronic image.
Photograph - is an image created by light falling on a light-sensitive surface usually photographic film or electronic image.

Basic Importance of crime
photography:
 Refresh memory
 Preserve memory
 Save money
Objectives Of Photography
1.To produce a pictorial record of the crime scene.
2.To help in keeping the police officer’s memory
inn remembering accurately as to where the
locations of physical evidence are found.
3.To help in securing and obtaining confession,
description, deposition and information relating to
the case. MARK LESTER FLORES 2012

USE OF PHOTOGRAPHY
 Identification
 Record
 Presentation
 Substitution
 Deciding factor

PRINCIPLES OF PHOTOGRAPHY
 A photograph is both the mechanical and
chemical result of photography. To produce a
photograph, light is needed aside from
sensitized materials (film or papers). Light
radiated or reflected by the subject must
reach the film while all other lights are
excluded. The exclusion of all other lights is
achieved by placing the film inside a light
tight box (camera).
 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 expose film called
development.

 The visual effect of light on the film after
development varies when the quantity
quality of light the reached the emulsion
of the film. To grant in the amount of light
will produce an opaque or very black
shade after development. Too little will
produces a transparent or white shade
after a development.
 The amount of light reaching the film is
dependent upon several factors like
lightning condition, lens opening, used,
shutter speed used, filter used etc.

FIVE ELEMENTS IN PHOTOGRAPHY:
1. Light or electromagnetic radiation
2. Camera
3. Sensitized materials
4. Chemical process
5. Subject or object – refers to animate
and inanimate things – persons or
materials etc..

Other photography related to
police photography
 Photomacrography
 Photomicrography
 Infrared photography
 Ultra – violate ray
photography

Light and Lenses
Lens - is an optical unit
mounted in the camera which
makes possible the formation of
sharp image.

What is LIGHT?
- is a form of electromagnetic impulse of
the same family as radio, hertzian waves,
heat, infrared, ultraviolet, x-rays and
cosmic rays.

Principle of LIGHT
- light, or visible light, is electromagnetic
radiation of a wavelength that is visible to
the human eye(about 400-700nm).
- in the context of science, light is
sometimes used to refer to the entire
electromagnetic spectrum.

Electromagnetic Spectrum
- is a continuum of all electromagnetic
waves arranged according to
frequency and wavelength. The sun,
earth, and other bodies radiate
electromagnetic energy of varying
wavelength. Electromagnetic energy
passes through space at the speed f
light in the form of sinusoidal waves.

Electromagnetic Spectrum

The wavelength is the distance from
wave crest to wave crest
Wavelength

Electromagnetic Radiation
 In terms of classical theory, the flow of
energy at the universal speed of light
through a material/ medium in the form of
the electric and magnetic fields that make
up electromagnetic waves such as radio
waves, visible light and gamma rays. In
such a wave, time- varying electric and
magnetic fields are mutually linked with
each other at right angles.

Measurement of light (expressed
in nanometer)
0 – 30 – X-ray
30 – 400 – Ultra – violate
400 – 700 – visible light
700 – 1000nm – Infrared light
1000 – up nm – Radio waves

The Visible Ray Of The Spectrum

Wavelength of the electromagnetic
Spectrum
Red
Orange
Yellow
Green
Blue
Violate

Objects Which Affect Speed Of
Light
 Transparent objects – objects or mediums
which merely slow the speed of light but allow
it to pass freely.
 Opaque objects – objects which divert or
absorb light, but allow no light to pass through it.
 Translucent objects – which allow light to
pass through them in such way that the outline of
the light source is not clearly visible. Ex. Glass,
ground glass oiled paper, water.

How Light Changes
Direction
1. Reflection – is a change in the direction
of light wave which occurs whenever light
waves comes in contact with the surface of
an object/subject but does not allow the
wave to pass through it.

Two ways how light
reflected:
 Diffuse reflected light - when light rays in
contact with rough surface.
 Specular reflected light – when light rays
come in contact with smooth surface such as
mirror, it produces glare.

Diffuse reflected
light
Specular reflected
light

2. Refraction – is the bending or redirection
of light waves when passing obliquely
from one medium to a medium of
different density.
A
B C
D
Refraction of light through flat glass

3. Prism – is a solid for dispersing light, it is
a transparent polygonal solid object with
flat faces and usually a triangular cross
section, used for separating white light into
a spectrum of colors. Light rays bend twice
when passing through a prism.
A Prism Bends A Ray Twice

A Prism Bends A Ray Twice

Significance of Lenses
 A lens is a piece of transparent material
with at least one curved surface, which
refracts, or bends light rays coming from
an object.
 Lenses are usually made out of glass or
plastic and they have special property
which can give good results.

Lens Type
1. Double convex
2. Plano convex
3. Concave convex
4. Double concave
5. Plano concave
6. Concave convex
7. Achromatic lens

Convex Concave

Converging rays – there is
convergence of light rays when light rays
meet at once point after they pass through
a lens. The point at which light converge is
called the focus.

Diverging rays – are lights rays
which bend away from a given point. Lenses
which cause light rays to diverge are known
as concave lenses.

Distinction
Converging rays
Diverging rays

Types Of Camera Lens
 Wide- angle lens
 Normal lens
 Telephoto
 Zoom lens
 Macro lens
 Micro lens

WIDE- ANGLE LENS
 Lenses have a shorter focal length usual
35 mm, 28mm or less
 Used when photographing narrow and
crowded

NORMAL LENS
 Lenses have a focal length of 25mm
to 26mm
 Lenses which are commonly used in
regular photography

TELEPHOTO
 Lenses have longer focal lengths
such as 90mm, 200 mm and longer
 Fixed lenses used in photographing
long or far distances.

ZOOM LENS
 Lenses which are variable. It can
photograph from the shortest to longest
distances.

MACRO LENS
 Lenses that enlarges object and
magnify from 1 to 9x.

MICRO LENS
 Used to photograph minute
objects and magnify and enlarge
from 10x up.

How lens affect photographic
images?
 Lens aberration – is an anomaly of the
which causes distortion of the image
due to lens curvature or color at the
edge of the lens.
 Aberration – as an optical distortion of an
image caused by a lens.

LENS DEFECTS:
 Chromatic aberration - caused by a
lens having a different refractive index
for different wavelengths of light.

Achromatic lens – a lens
corrected to bring together the yellow
and blue – violet rays so that no color
fingers will appear in the final image.

 Parallax error – is an apparent
displacement of an object when viewed
at two different angles or when the
person looking at the object changes
position.

Parallax error

 Astigmatism – a fault of a lens, caused
by slight non- uniformity of refraction which
prevents a sharp focus being obtained
simultaneously upon both vertical and
horizontal lines.

v Astigmatism

 Aspherical lens – a lens in which
one surface departs from a true
spherical aberration.

Basic Parts Of Camera
Light thigh box
Lens
Shutter
A shutter release
Holder Of Sensitized Materials
View finder

Basic Parts Of Camera

Camera Body
 Light thigh box – located in the body is
a light proof compartment in which film
is held and expose.
- exclude unwanted light that might
expose the sensitized materials or film.
It is an enclosure that devoid light.

SHUTTER
 Is a spring activated mechanical device,
keeps light from entering the camera
except during the interval of exposure.
 Control light the length of time that light
enters a camera, a shutter placed
behind the diaphragm.

How a Shutter Works:
 Shutter speed – the length of time it
takes for the spring to pull the hole past
the lens opening.
Shutter release – is the button you push
to take a picture. It opens the shutter so that
light comes into the camera and forms an
mage on the film.

Holder Of Sensitized
Materials
 It is located at the opposite side of the
lens.
 Its function is to hold firmly the
sensitized material in its place during
exposure to prevent formation blurred
image of the subject.

VIEW FINDER
 It is an instrument in determining then
field of view of the camera or the extent
of the coverage of the lens.

Camera Basic Operations

Types Of Camera
 Single lens reflex (SLR) camera – this
type of camera allows the photographer
to view a subject through the main lens of
the camera.

SLR Mechanics

SING LENS REFLEX CAMERA

Instant Camera/Polariod
camera -

t  Twins-lens Reflex Camera or TLR
(21/ 2 Camera system, one of which
focuses on the film when the shutter
is opened. The other reflects a similar
image up toward the top of the
camera and focuses it upside down
and reversed on a ground glass
screen.

Twins-lens Reflex Camera

 VIEW FINDER CAMERA

VIEW FINDER MECHANICS

FILM
 Film contains minute grains of silver
halide suspended in animal gelatin and
coated on celluloid material.
 Is a sheet of celluloid used as a base for
photographic sensitive material.
 A cellulose tape or plate where silver salts
are suspended, capable of recording
light.

The Basic Parts of the Film
 Base
 Emulsion
 Anti – halation banking

Film Base
 A film is a transparent substrate which acts
as a support medium for the
photosensitive emulsion that lies atop it.
Despite the numerous layers and coatings
associated with the emulsion layer, the
base generally accounts for the vast
majority of the thickness of any given film
stock.

Emulsion
 A suspension of a sensitive silver salt or a
mixture of silver halides in a viscous
medium ( as a gelatin solution) forming a
coating on photographic plates, film or
paper.

Anti – halation banking
 A layer found in modern photographic film. It
is placed between the light sensitive
emulsion and the tough film base, or
sometimes on the back of the film base.
 The light that passes through the emulsion
and the base is absorbed by the opaque
anti-halation layer.

Characteristics of B & W
Films
 Emulsion speed
 Spectral sensitivity
 Granularity or Graininess
Emulsion speed
a.ASA (American Standards Associations) rating.
This is expressed in arithmetical value.
b.DIN (Deutsche Industrie Normen) rating, which
expressed in the logarithmic value.
c.ISO (International Standards Organization)
rating. This is expressed in the combined
arithmetical and logarithmic value.

 Spectral sensitivity
a. Blue sensitive film – sensitive to UV
rays and blue color only.
b. Orthochromatic film – sensitive to UV
rays , to blue and green color. It is not
sensitive to red color only.
c. Panchromatic film – sensitive to UV
radiation to blue, green and red light or
all colors.
d. Infrared film – sensitive to UV rays, to
blue, green, red light and infrared rays.

 Granularity or Graininess
- this refers to the size of the metalic
silver grains that are formed after
development of an exposed film.
- generally, the size of metallic silver
are dependent on the emulsion speed of
the type of developing solution that is
used in processing.

 Film speed – film sensitivity to
light.
 Shutter speed – how long light
is allowed through the lens.
 Lens speed – largest opening of
a lens ( smallest f/-number)

EXPOSURES
 Is making a photographic record by
exposing sensitive material to light
action, the quantity of light allowed to
act is expressed in terms of the length
of time the action is allowed to continue
with effective lens aperture used.
 Is a simply a combination of the
aperture and shutter speed.

 Over exposure – refers to film
exposure with too great light action
resulting from a long period of
exposure with too large lens opening.
 Under–exposure – refers to
insufficient light action during
exposure, too high shutter speed, too
small lens aperture or a combination
of the factors.

Lens Opening
The size of lens opening is
referred to as the f-stop or 1-
number.
As the f-stop decreases, the size
of the lens opening increases. It
gets bigger in such a way that
each lends opening lets in exactly
twice as much as the preceding
opening. MARK LESTER FLORES 2012

 Diaphragm – the mechanical device
which allows and conveniently to adjust
the aperture.
- It is an integral part of the lens system.
- It is a thin opaque structure with an
opening (aperture) at its center.
- The role of diaphragm is to STOP the
passage of light, except for the light
passing through the aperture.

 Filters – a sheet of colored material
that is placed before the camera lens,
which absorbs certain colors and
allows other to pass through.

 Focal distance – distance of any obejct
upon which the lens is focused.
 Focal plane – the palne in which sharp
focus lies. Regarded as the surface of
the film or plate.

 Depth of field – the distance from the
closest clear object in a photograph to
the farthest clear object; the nearest and
farthest distance apparently in sharp
focus on a given object being
photographed.

Concept of Exposure
We expose film to light so that image of
the object or subject will be recorded in the
sensitized material through the manipulation of
lens aperture and shutter speed. Exposure
determines how much light gets to the film. The
amount of light allowed to get inside the camera to
reach the sensitized material (film) is controlled by
the lens aperture and shutter speed. The
combination of the two is necessary to capture the
proper quantity of light.

FILM DEVELOPMENT
 A process whereby photographic film is
treated after photographic exposure to
produce the desire negative or positive
image.
 The process transforms the latent image
into a visible image and makes it
permanent.

 Film developer – it is a chemical agent
or solution (in Kodak developer, D-76 is
used) which causes development to
take place.
 Stop bath – an acid bath which
instantly checks the process of
development.
 Fixer – a solution used for removing
the residual sensitive silver from a
development film thereby rendering the
image permanently.

 Over – development – refers to
development at too long a time at too
high temperature resulting in excessive
contrast.
 Under – development – means
insufficient development due to either
solution is too weak or overworked; too
low temperature, insufficient agitation
thus resulting in a thin negative lacking
contrast.

Cardinals in Film Development
 Developing
 Washing
 Stop bath
 Fixing
 Washing / Rinsing
 Drying

QUESTIONS

Thank you

Name: MARK LESTER M. FLORES
Status: Married
Age: 22, years old
B- DAY : Dec 4, 2013
Connected: Gov. Alfonso D. Tan College
Tangub CITY
Contact # : 09061424768

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