CRIMINALISTICS
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Personal Identification
Police Photography
Forensic Ballistics
Questioned Documents
Polygraphy
Forensic medicine
FORENSIC SCIENCE
Refer to the application of principles of
various science to law.
It is a course or a group of subjects
which uses principles of various
studies that would dive light to
certain legal issues.
CRIMINALISTICS
It refers to the application of the principles of
various science in solving problems in
connection with the administration of justice.
Sometimes refers to forensic science or police
sciences, although in a strict sense it is
merely a branch of forensic science that deals
with physical evidence that has to be
collected preserved, examined and compared
in other to serve the ends of justice.
CRIMINALISTICS
The word forensic was derived from the latin
word “FORUM” which means “the market
place”, a place where people gathered for
“public discussion”.
When it is used in conjunction with other sciences
it simply connotes the idea of application to
law or for the administration of justice.
Sometimes it is also referred to as “legal”.
PERSONALITIES
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Dr. Hans Gross
Dr. Paul Kirk
August Vollmer
Dr. Hans Gross
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Father of Modern Criminalistics
An Australian magistrate to
described “Search for Truth” as the
ultimate goal of all investigate and
detective works.
Dr. Paul Kirk
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Father of Criminalistics in U.S.
August Vollmer
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The head of the first comprehensive
Crime Laboratory in U.S. established
in Los Angeles.
PHOTOGRAPHY
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is a technological invention that has
become the most universal means of
communication and artistic
expression the world has known. It
overcomes the barrier of language
difference.
The most universal of all languages
PHOTOGRAPHY
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It is an art or science that deals with
the reproduction of image through
the action of light, upon sensitized
materials (film or paper) with the aid
of camera and its accessories, and
the chemical process involved
therein.
JOHN F. W. HERSCHEL
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first PHOTOGRAPHIC CHEMIST
Popularized the word “photography” derives from
the Greek words
“phos” or “photos” which means Light and “grapho”
means writing or “graphia” meaning to draw.
He suggested the terms “NEGATIVE” and “POSITIVE”
to distinguish the key stages of the photographic
image and coined the word “SNAPSHOTS”.
Henry Fox Talbot
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1840 – discovered the method of developing paper
negative images that greatly reduces the exposure required
in the camera.
He patents the “CALOTYPE” process, later called TALBOTYPE
– negatives on paper sensitized with silver iodine and silver
nitrate. These were contact but DAGUERREOTYPE was
better.
CALOTYPE creates permanent (negative) image using paper
soaked in silver chloride and fixed with salt solution.
Talbot created positive images by contact printing onto
other sheet of paper.
LOUIS JACQUES MANDE DAGUERRE
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Father of Photography
perfected photography’s chemical processing
DAGUERREOTYPE (1889)– the first practical
photography process. Image was made
permanent by the use of “HYPO”
HYPO – an anti-staining agent like acetic acid, a
preservative like sodium sulfite, and a
hardening agent like potassium alum (sodium
thiosulfate)
JOSEPH NICEPHORE NIEPCE
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1816 – was able to obtain camera images on paper
sensitized with silver chloride solution. Fixation was
partial.
Combines the camera of obscura with
photosensitive papers.
He produced the first permanent photograph in
1825
Prior to Niepce people just used the camera
obscura for viewing or drawing purposes not for
making photographs
THOMAS WEDGWOOD
and HUMPHREY DAVY
produced “PHOTOGRAMS” no camera was used
but still can photograph by placing an
opaque object such as shell or a leaf on
paper with silver nitrate solution and
exposing it to sunlight (but none of this
work was permanent.) 1777 – light
sensitivity of silver nitrate and silver chloride
solution has been discovered and
investigated
George Eastman
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He developed dry gel on paper or
film, to replace the photographic
plate so that a photographer no
longer needed to carry boxes of
plates and toxic chemical around.
EASTMAN KODAK COMPANY
POLICE PHOTOGRAPHY
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Is the application of the principles of
photography is relation to the police
work and in the administration of
justice.
PHOTOGRAPH
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Is the mechanical and chemical
(positive) result of photography.
Picture and photograph are not the
same for the picture is a generic term is
refers to all kind of image while
photograph is an image that can only be
a product of photography.
PICTURE
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Derived from the Latin word
“pictura” or “pictus” which means
“to paint”.
It is design or representation made
by various means such as painting,
drawing, or photography.
NEGATIVE
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A material showing a negative
(latent) photographic image on
transparent material used for
printing positive picture
(photograph) as a result of chemical
processing.
USES OF PHOTOGRAPHY
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9.
Personal Identification
For Communication
For Record Purposes
For Preservation
For Discovering and Proving
For Court Exhibits
Crime Prevention
Police Training
Reproduction and Copying
Personal Identification
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Personal identification is considered to
be the first application of photography
in police work.
Alphonse Bertillion was the first police
who utilized photography in police
work as a supplementary identification
in his Anthropometry system.
For Communication
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Photograph is considered to be one
of the most universal method of
communication considering that no
other language can be known
universally than photograph.
For Record Purposes
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Considered to be the utmost used of
photography in police work.
Different Views in Photographing
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General View (long-range)
Medium view (medium range)
Close-up View (Short range/ mug
shot)
Extreme Close-up View
Different Views in Photographing
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General View (long-range)- taking an
over-all view of the scene of the crime .
It shows direction and location of the
crime scene.
Medium view (medium range) – is the
taking of the scene of the crime by
dividing it into section. This view will
best view of the nature of the crime.
Different Views in Photographing
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Close-up View (Short range/ mug shot) – is the
taking of individual photograph of the evidence
at the scene of the crime. It is design to show
the details of the crime.
Extreme Close-up View- commonly designed in
laboratory photographing using some
magnification such as photomacrography and
photomicrography
For Preservation
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Crime scene and other physical evidence
requires photograph for preservation
purposes.
Crime scene cannot be retain as is for a long
period of time but through photograph the
initial condition of the scene of the crime can
be preserved properly.
For Discovering and Proving
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Photography can be extend human
vision in discovering and proving
things such as:
a. The use of magnification
b. Used of artificial light
For Discovering and Proving
a.
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The use of magnification
Photomicrography
Photomacrogaphy
Microphotography
Macrophotography
Telephotography
The used of magnification
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Photomicrography – taking a magnified
photograph of small object through attaching
camera to the ocular of a compound
microscope so as to show a minute details of
the physical evidence.
Photomacrogaphy – taking a magnified
(enlarged) photograph of small object by
attaching an extended tube lens (macro lens) to
the camera.
The used of magnification
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Microphotography - is the process of reducing into
a small strips of film a scenario. It is first used in
film making.
Macrophotography – used synonymously with
photomacrography.
Telephotography – is the process of taking
photograph of a far object with the aid of a long
focus and telephoto lens.
PROCESS
PRODUCT (MAGNIFIED
PHOTOGRAPH)
Photomicrography Show minutes details
Photomacrography Enlarged photograph
Microphotography Reduced image
Telephotography Image of far distance
object
For Discovering and Proving
b. Used of artificial light- such as x-ray,
ultra violet and infra-red rays to
show something which may not be
visible with the aid of human eye
alone.
For Court Exhibits
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Almost all evidence presented in court before
formally be accepted requires that they satisfy the
basic requirements for admissibility which is
relevancy is usually proved by proving the origin of
the evidence and its relation to the case and this is
usually supplemented by photograph of the
evidence giving reference as to where it came from.
Ideal size for court presentation is about 5”x7” for
the enlargement prurposes.
Crime Prevention
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With the used of video camera (hidden
camera) and other advanced photographic
equipment crime are being detected more
easily and even to the extent of preventing
them from initially occurring.
Police Training
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Modern facilities are now being
used as instructional material not
only in police training as well as in
other agencies.
Reproduction and Copying
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With the use of photography any number
of reproduction of the evidence can be
made those giving unlimited opportunity
for its examination and even allow other
experts or person to examine the specimen
without compromising the original.
ESSENTIALS OF PHOTOGRAPHY
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LIGHT
CAMERA
LENS
SENSITIZED MATERIALS
CHEMICAL PROCESS
LIGHT
Is an electromagnetic energy that
travels in a form of a wave with the
speed of 186,000 miles per second
camera
A light tight box designed to block
unwanted or unnecessary light from
reaching the sensitized materials.
Lens
Is the light gathering mechanism of the
camera that collect the reflected light
coming from the object to form the
image.
Sensitized materials
Composed of highly sensitized chemical
compound which is capable of being
transformed into an image through the
action of light and with some chemical
processes (film and photo paper)
Chemical process
Is the process necessary for reducing
the silver halides into a form so as a
latent image and a positive image be
made resulting to what we called
photograph.
Theories of light
1. The Wave Theory (Huygens)
2. Corpuscular Theory (Newton)
3. Modified Wave Theory (Maxwell and
Hertz)
4. Quantum Theory (Albert Einstein)
The Wave Theory (Huygens)
It is the theory that was transcribed
from the motion of the water that if we
observe a piece of log floating in the
ocean and with the force of the air
would naturally will make the log move
up and down.
Corpuscular Theory (Newton)
This later opposed the wave theory
stating that light has its effect by the
motion of very small particles such as
electrons.
Modified Wave Theory (Maxwell and Hertz)
•Based on electromagnetic.
•All these theories are still considered to be
of little lacking that law enforcement need
not to be very focus on this but rather go
along with the accepted conclusion that
lights is a form of energy, which is
ELECTROMAGNETIC in form
LIGTH
•Is an electromagnetic energy with the speed of
186,000 miles per second.
•Its wave travel is said to be characterized in
certain extend based on velocity, wavelength
and frequency of the number of vibration of the
wave per second.
Light Wavelength
•Is the distance measured between the two (2)
successive crest or through of wave and it is
expressed in either mill micron (nanometer) or
Angstrom.
BEHAVIOR OF LIGHT CAN EITHER BE:
•Reflected
•Transmitted
•Absorbed
BEHAVIOR OF LIGHT CAN EITHER BE:
•Reflected
•Is the action of light once the light hits a
mirror and it bounce back.
BEHAVIOR OF LIGHT CAN EITHER BE:
•Transmitted
•When the light hits a transparent glass
which would allow the light to pass
through its medium.
BEHAVIOR OF LIGHT CAN EITHER BE:
•Absorbed
•When the light hits a dark colored object
and prevents it from either bouncing or
passing through.
TYPES OF LIGHT
•Visible light – is the type of light that produces
different sensation when reach the human eye. It is
the type of light, which is capable of exciting the
retina of the human eye.
•Invisible light – light in which their wavelength are
either too short or too long to excite the retina of the
human eye. Example- xray, ultra-violet and infra-red
light.
Photographic Rays
•X-ray (.01-30) (Roentgen rays)
•Ultra-violet (30-400) Black Light
•Visible Light (400-700)
•Infra-red (700-1000) (Heat rays)
Photographic Rays
•X-ray (.01-30) (Roentgen rays)
•Ultra-violet (30-400) Black Light
•Visible Light (400-700)
•Infra-red (700-1000) (Heat rays)
Photographic Rays
•X-ray (.01-30) (Roentgen rays)
•USES: examination of fractures,
dislocation, foreign object inside the body,
hemorrhage using the principle of shadow
or internal photography.
Photographic Rays
•Ultra-violet (30-400) Black Light
•It appears before the violet color, of the
visible light spectrum.
•USES: erasures, invisible writing, contact
writing water-soaked documents, latent
print blood, semen and fiber.
Photographic Rays
•Visible Light (400-700)
•USES: DOST
•Direct light exam
•Side Light Exam (Erasure)
•Oblique Light Exam (erasure and intended
writing)
•Transmitted Light exam (from the back or
bottom) (watermarking)
Photographic Rays
•Infra-red (700-1000) (Heat rays)
•Appears beyond the red color of the
visible light spectrum.
•USES: addition, interlineations,
obliteration, charred documents, night
vision, remote control.
SOURCES OF LIGHT
•NATURAL LIGHT
•ARTIFICIAL LIGHT
SOURCES OF LIGHT
•NATURAL LIGHT
•Natural lights are lights which some to
existence without the intervention of man.
•The source of all daylight is the sun.
•The combination or contrast ascertain the
quality of daylight.
NATURAL LIGHT
•Bright – objects in open space cast a deep and uniform
shadow. the source of the light is not covered and the
object or subjects appear glossy in coming from the sky.
•Hazy – objects in open space cast a transparent shadow
- thin clouds cover the sun and the shadow appears
bluish because decrease of light falling on the subject in
open space.
•Dull – objects in open space cast no shadow
- the sun is totally covered by thick clouds.
SOURCES OF LIGHT
•ARTIFICIAL LIGHT
•Artificial lights are lights, which are man
made.
•Almost all artificial sources can be used in
photographing of objects, as long as the light
is capable of exposing the sensitized materials
(film)
Artificial Light
•Continuous radiation – incandescent
bulb, fluorescent lamp,photoflood lamp,
etc.
•Short Duration – Chemical flash (flash
bulb), electronic flash
PHOTOFLOOD LAMP
•Is likewise known as reflectorized light
or spot light . It is a light with a reflector
at the back which focus the light to the
object the common wattages of this
lamp is 500 watts.
FLOURESCENT LAMP
•are tube lamps in which the walls are
coated with fluorescent powders with
both ends is mounted with a holder that
serves as the reflector . This is
commonly used in photographing.
INCANDESCENT BULB
•Are bulb with a wire filament
connecting two wires which sustain the
electrical charge that produces the light.
•Everyone likewise commonly uses this
although it is more expensive in terms of
electrical consumptions.
FLASH BULB
•Are chemical lamps, as it generate light
by the rapid combination of metal in
oxygen.
•The bulb cab be used only once as the
bulb busted when fired electrically.
ELECTRONIC FLASH
•Produces light by an instantaneous
electrical in charges between two
electrodes in a gas filled glass bulbs.
•The electrical energy for discharge is
kept in capacitor or condenser.
SENSITIZED MATERIALS
•It refers to the film and photographic
paper that basically composed of
emulsion containing silver halides
suspended in gelatin and coated on a
transparent or reflective support.
PARTS OF SENSITIZED MATERIALS
1. Emulsion- is that part of the film or
photographic paper sensitive to light. In a
colored film this emulsion surface can be
composed of three layers (blue, green and
red) with filters intervening.
2. Anti-halation backing- is the one designed
to hold back the light and prevent halation.
3. Base- Support the emulsion.
TYOES OF FILM
ACORDING TO USE
a. Black and white film
b. Colored film
BLACK AND WHITE FILM
•Usually represented by a prefix or a
suffix “pan” or “ortho” and generally
used in black and white photography.
•Examples are otholith film, tri x-pan and
pan X-plus.
COLORED FILM
•Colored film can be dived in two:
Negative type represented by the “color” to
which it is sensitive.
Reversal Type represented by the word
chrome. example: blue sensitive film, ultraviolet film, infra red film, orthochromatic film
and panchromatic film.
According to Spectral Activity
1.
2.
3.
4.
Blue Sensitive
Ortochromatic
Panchromatic
Infrared
According to Spectral Activity
1. Blue Sensitive – sensitive to
ultraviolet rays and blue only
2. Ortochromatic – sensitive to
ultraviolet rays, to blue and green
color. Not sensitive to red color.
According to Spectral Activity
3. Panchromatic – sensitive to
ultraviolet rays, to blue, green and
red color (all colors).
4. Infrared – sensitive to ultraviolet
rays, to all the colors, and infra red
rays.
FILM SPEED
The extent to which an emulsion is sensitive to light is referred to as its emulsion speed.
Two general types of speed ratings are:
1.
ASA (American Standards Association) rating – This is expressed in arithmetical
value system. The speed in numbers is directly proportional to the sensitivity of the
material. A film with an arithmetical value of 400 is four times as fast as one with a
speed of 100.
Example: ASA 400
2.
DIN (Deutche Industri Normen) rating – This is expressed in logarithmic value
system. In this system an increase of 3 degrees double the sensitivity of the film.
Example: 27º DIN
3.
ISO (International Standards Organization) rating – Combination of ASA and DIN
Example : ISO 400 / 27º
PHOTOGRAPHIC PAPER
•It is that sensitized material that will
record the visible image in the final
development and become photograph.
TYPES OF PHOTOGRAPHIC PAPER
a. According to emulsion used (silver
halides content)
b. According to physical characteristics
c. According to contrast (grade)
According to emulsion used
CHLORIDE PAPERS- these insensitive paper are suitable
for contact printing, and yield warm toned images by
development.
BROMIDE PAPERS- papers with pure silver bromide
emulsion are sensitive and produce neutral black or
“cold” blue black image, suitable for enlargement.
CHLOROBROMIDE PAPERS- containing a blend of silver
chloride and silver bromide salts, these emulsions
produce papers sensitive enough to be used for enlarging
and contact printing.
According to physical characteristics
•Weight
•Surface texture
•Color
WEIGHT
•LIGHT WEIGHT- designed for high flexibility and when
paper thickness is not of consideration. Indented for
purposes, which involves folding.
•SINGLE WEIGHT – papers used for small prints or which
are needs to be mounted on solid and fine details
necessary in the production. Used in ordinary
photographic purposes.
•MEDIUM WEIGHT – good for enlarging purposes.
•DOUBLE WEIGHT – generally used for large prints
because they stand up under rough treatment.
SURFACE TEXTURE
•Glossy paper- designed for fine details and
brilliant image formation.
•Semi-mate paper- obscure the fine details
•Rough papers- used for large prints or
where breath rather than details is
necessary.
COLOR
•White- better used in police
photography
•Cream- preferred for pictorial effect,
portraits, landscape or when warmth
effect is desired.
•Buff papers- prepare for tone prints.
ACCORDING TO CONTRAST
•Volex #0- used for printing extremely contrats negative or
extremely exposed film.
• Volex #1- used for high contrast negative (over exposed film)
• Volex #2- use for normal exposed film
• Volex #3- used for negative with weak contrast(under exposed)
•Volex #4- used to provide sufficient contrast to compensate for
very thin or weak negatives. It is useful imprinting which high
contrast desired.
•Volex # 5- for flat negative that are unprintable.
CAMERA
•Is a light tight box with light gathering
device and a means of blocking
unwanted or unnecessary light from
reaching the sensitized materials.
CAMERA
•BASICALLY, camera can produce image
with its four basic parts such as , light
tight box, lens, shutter and holder of
sensitized materials , GENERALLY there
are five important parts includes the
view finder.
ESSENTIAL PARTS OF A CAMERA
•LIGHT TIGHT BOX- a box designed to keep light
out and serve as a frame to hold other parts.
•LENS- designed to collect or to focus the
reflected light from an object to form an image
on the film
•SHUTTER- designed to control the time during
which the light reaches the film.
ESSENTIAL PARTS OF A CAMERA
•HOLDER OF THE SENSITIZED MATERIALSlocated at the opposite side of the lens designed
to hold firmly the sensitized material to prevent
the formation of the multiple or blurred image.
•VIEWFINDER- designed to determine the filed
of view of the camera or the extent of the
coverage of the given lens.
TYPES OF THE CAMERA
•VIEW FINDER TYPE- it is considered as the
smallest and the simplest type of camera.
•SINGLE LENS REFLEX CAMERA- it is a type
of camera best suited for police work due to
its interchangeability of the lens.
TYPES OF THE CAMERA
•TWIN LENS REFLEX CAMERA- a type of
camera with dual lens, one for focusing and
the other for forming the image.
•VIEW OF PRESS TYPE- is considered the
biggest and expensive type of camera, used
for movie making.
PINHOLE CAMERA
•The simplest camera made from a box
with a small hole in one of its sides.
POLAROID
•A type of camera that immediately
produce a positive prints.
•Designed by Edwin H. Land
FISH EYE LENS
•Special type of camera having 180
degrees angle of view.
FOLDING CAMERA
•A type of camera in which the lens and
the shutter mounted to body by means
of an accordion-pleated bellows, which
can be folded into camera foe ease of
carrying.
LENS
•It is the image-forming device of the lens that
actually has a greater effect on the quality of the
image to be formed.
•A medium or system which converge or diverge light
rays passing through it to form an image.
•Can be a glass or transparent material, which permit
light to pass through and change the direction of
light.
DANIEL BARBARO
First to introduce the use of lens in the
camera.
TYPES OF LENS
•Normal Lenses
•Wide angle Lenses
•Telephoto Lenses
•Zoom Lenses
•Auto Focus lenses
•Macro Lenses
TYPES OF LENS
•Normal Lenses
•It is the standard equipment on a camera and is the
intermediate between WIDE ANGLE AND TELEPHOTO
LENSES.
•This picture angle of a normal lens is 45 DEGREE, which
corresponds to the viewing angle of the human eye.
•NORMAL LENS allow you to view your subject nearly
the same as your unaided eye, neither reducing nor
enlarging the image.
TYPES OF LENS
•Wide angle Lenses
•It has SHORTER FOCAL length than the NORMAL
LENS.
•It covers a PICTURE ANGLE WIDER THAN 60
DEGREES.
•It enables photography of a widely extended
scene from a close proximity within a confined
area.
TYPES OF LENS
•Telephoto Lenses
•A telephoto, or LONG FOCUS lens have a
LONGER FOCAL LENGTH and provide a CLOSEUP IMAGE OF A DISTANT SUBJECT.
•It also covers a smaller field of view and a
shallower depth of field.
TYPES OF LENS
•Zoom Lenses
•Zoom optics offer the advantages of rapid
changing of focal length without changing
lenses and having one lens serve the purpose
of several, being both economical and space
saving.
TYPES OF LENS
•Auto Focus lenses
•Zoom optics offer the advantages of rapid
changing of focal length without changing
lenses and having one lens serve the purpose
of several, being both economical and space
saving.
TYPES OF LENS
•Macro Lenses
•It is designed primarily for close-up work.
•The advantage of macro lens for police work is
that they can focus on small articles of evidence
such as fingerprints at the scene or in the crime
laboratory without the use of microscope or lens
attachments.
CLASSIFICATION OF LENS
•According to the type of image to be produced.
•Positive or convex lens (converging lens)
•Negative or concave lens (diverging lens)
•According to degree of correction
•Menicus lens
•Rapid rectilinear lens
•Anastigmat lens
•Achromatic lens
•Apochromatic lens
•According to the type of image to be produced.
•Positive or convex lens (converging lens)characterized by the fact that it is thicker at the
center and thinner at the side which is capable of
bending the light together and forms the image
inversely.
•Negative or concave lens (diverging lens)characterized by the fact that is thinner at the
center and thicker at the side and forms the virtual
image on the side of the lens.
•According to degree of correction
•Menicus lens- lens that has no correction
•Rapid rectilinear lens- lens corrected of
distortion
•Anastigmat lens- correcting astigmatism
•Achromatic lens- correcting chromatic
aberration
•Apochromatic lens- correcting both
astigmatism and chromatic aberration.
INHERENT LENS DEFECTS
•Spherical Aberration
•Coma
•Curvature of Field
•Distortion
•Chromatic Aberration
•Astigmatism
•Chromatic Difference of Magnification
•Flares
INHERENT LENS DEFECTS
•Spherical Aberration
•Inability of the lens to focus light passing the side
of the lens producing an image that is harp in the
center and blurred at the side.
•It is a lens defect that can affect resolution and
clarity.
•It is the blurredness due to lens passing the side
(off center) of the lens.
INHERENT LENS DEFECTS
•Coma
•Also known as the lateral aberration
•Inability of the lens to focus light that travels straight or
lateral, thus making it blurred while the light reaching the
lens oblique is the one the is transmitted sharp.
•Positive Coma results in a comet style tails scattering
radically towards its optical axis.
•Negative Coma scattering radically away from optical axis.
INHERENT LENS DEFECTS
•Curvature of Field
•The relation of the images of the different
point are incorrect with respect to one
another
INHERENT LENS DEFECTS
•Distortion
•Is a defect in shape not in sharpness.
•It can either be Pincushion distortion
(curving outward) or barrel (curving
inward).
INHERENT LENS DEFECTS
•Chromatic Aberration
•Inability of the lens to focus light of varying
wavelength.
•The lens refracts rays of short wavelength more
strongly than those of longer wavelength and
therefore bringing blue rays to a short focus than
the red.
INHERENT LENS DEFECTS
•Astigmatism
•Is a form of lens defects in which the
horizontal and vertical axis are not equally
magnified.
•Inability of the lens to focus both horizontal
and vertical lines.
INHERENT LENS DEFECTS
•Chromatic Difference of Magnification
•Variation in the size of the image produced
by an optical system with the wavelength (or,
equivalently, color) of light. Also known as
lateral chromatic aberration.
INHERENT LENS DEFECTS
•Flares
•Condition of the lens producing
multiple images.
LENS CHARACTERISTICS
1.
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2.
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3.
Focal Length
Wide angle or short focus
Normal or medium focus
Long or telephoto lens
Zoom lens
Relative aperture
Depth of filed
Hyper focal distance
Depth of focus
Focusing
LENS CHARACTERISTICS
1.
Focal Length- is the distance measured from the optical
center of the lens is set to focus at infinite position. As
according to focal lenses may be classified as:
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Wide angle or short focus- with focal length not longer
than diagonal ball of the negative. Useful in taking
photograph at shirt distance with wider area coverage
(.35mm)
•
Normal or medium focus- with focal length
approximately equal but no longer than twice the
diagonal half of the negative (>35<70mm)
LENS CHARACTERISTICS
1.
Focal Length- is the distance measured from the optical
center of the lens is set to focus at infinite position. As
according to focal lenses may be classified as:
•
Long or telephoto lens- with focal length longer than
twice the diagonal half of negative. Best used in long
distance photographing but with narrow area coverage.
(>70mm)
•
Zoom lens- lens with variable focal length or that which
can be adjusted continuously by the movement of one or
more elements in the lens system. A combination of
positive and negative lens.
LENS CHARACTERISTICS
2.
Relative aperture- the light gathering poser of the
lens expressed in f-number.
•
Depth of filed- is the distance measured from the
nearest to the farthest object in apparent sharp
focus when the lens.
•
Hyper focal distance- is the nearest distance at
which when a lens is focused with a given
particular diaphragm opening will gives the
maximum depth of field.
LENS CHARACTERISTICS
3. Focusing
• is the setting of the proper distance in
order to form sharp image.
• Its basic purpose is to subtract (control)
light rays of varying wavelengths.
FILTERS
•Homogenous medium (plastic or glass)
which absorbs and transmits different
light rays passing through it.
•Its basic purpose is to subtract (control)
light rays of varying wave lengths.
FILTER FACTOR
•Refers to the number of times that the
normal exposure must be multipled.
TYPES OF FILTER
•Correction filter
•Used to change the response of the film so that all
colors are recorded at approximately the relative
brightness values by the eye.
•Contrast filter
•Used to change the relative brightness so that the two
colors which would otherwise be recorded as nearly the
same will have decidedly different brightness in the
picture.
TYPES OF FILTER
•Haze filter
•Used to eliminate or reduce the effect of serial haze.
•Neutral density filter
•Used for recording the amount of light transmitted
without changing the color value.
•Polarizing filter
•Used to reduce or eliminate to much reflections on highly
reflective surfaces such as newly painted object which has
high glossiness.
CHEMICAL PROCESS
•the process of making the latent image visible and
permanent.
•DEVELOPMENT(use either d-76, dektol or universal
solution)
•Is the process necessary for reducing the silver halides to
form the image.
•ELON, HYDROQUENONE- used as main developing agents
CHEMICAL PROCESS
•STOP BATH normally composed of water with little
amount of dilute acetic acid that serves as a means to
prevent contamination between the developer and the
acid fixer.
•FIXATION is the process by which all unexpected silver
halides are dissolved or removed from the emulsion
surface and making the image more permanent.
•SODIUM THIOSULFATE(HYPO) is the main fixing agent
that dissolves unexposed silver halides.
OTHER CHEMICAL USED
•Acetic Acid and Boric Acid- serves as
neutralizer
•Sodium Sulfate- serves as the preservative
•Potassium bromide- restrainer or hardener
•Sodium Bicarbonate and Borax Powder- serves
as accelerator
OTHER PROCESSES/ ADJUSTMENT IN
DEVELOPING:
•DODGING- is the process of eliminating unwanted
portion of the negative during enlarging
•CROPPING- is the process of omitting an object
during the process of enlarging and printing
•VIGNETING – is the gradual fading of the image
towards the side through skillful adjustment on the
dodging board.
OTHER PROCESSES/ ADJUSTMENT IN
DEVELOPING:
•DYE DONING is the process designed in
changing the color tone of the photograph
•BUENING-IN refers to additional exposure on a
desired portion of the negative used for
purposes of making a balance exposure
“Recipe for success: Study while others
are sleeping; work while others are
loafing; prepare while others are playing;
and dream while others are wishing.” ~
William A. Ward