Review Notes for Photography

Cagayan de Oro City

Review Notes in Photography

By: JOHNNY REY D CAILING, RC, CSP

Former Program Dean, Christ the King College

At Present Professor, Capitol University

What is Photography?

• -is the production of visible images by using the action of light on a sensitized material.
• The word photography was derived from two Greek terms “PHOTOS” which means light and “GRAPHIEN” which means to write. Thus, literally, photography means to draw with light.

What is Forensic?

-is derived from the Latin word “forum” or a market place where people are gathered for public discussion.

Modern Definition of Photography

• -Is an art or science which deals with the reproduction of images through the action of light, upon sensitized materials, with the aid of a camera and its accessories, and the chemical process involved therein.

Distinction between Technical Photography from Forensic Photography

• Technical photography concepts and principles which includes characteristics of photographic rays, the use of camera, lenses, filters, structure of film and photographic papers, chemical processing and others.
• Forensic photography covers investigative photography, preparation of mug file and crime scene photography.

The First Landmark use of Photography in Police History

• Bertillon System- photograph was use to supplement the classification system.
• Fingerprint- the photograph is still placed on his finger print card not to supplement the identification system but to have available photograph if needed for investigation purpose.

Significance of Photography in the field of Investigation (Police Works)

• A photograph of the crime scene is a factual reproduction and accurate record of the crime scene because it captures TIME, SPACE AND EVENT. A photograph is capable of catching and preserving the:
• SPACE - the WHERE of the crime (Locus Criminis)
• TIME – the WHEN of the crime
• EVENT – the WHAT of the crime – what is the nature or character of the crime?

Photography, Its Principle

• A photograph is a mechanical result of photography.  To produce a photograph, light is needed aside from sensitized material (films and photographic papers). Light radiated or reflected by the subject must reach the sensitized material while all other lights must be excluded. The exclusion of all other lights is achieved by placing the sensitized material inside a light tight box (camera). The light maybe visible or invisible.

Uses of Photography in the Police Work

• Identification files, Communication and microfilm files, Evidence, Offender detection, Court exhibits, Reproduction or Copying, Personnel Training, Crime and Fire Prevention, and Public Relations.

Special Uses of Photography

• INFRARED PHOTOGRAPHY -Infrared photography is the recording of images formed by infrared radiation. Because infrared radiation is invisible, some special techniques may be needed.  But, in general, most of the commonly required methods are as simple as those of ordinary photography. These uses special films that is sensitive to infrared radiation.
• Infrared rays which are invisible have a longer wavelength than visible light. They can penetrate haze that scatters the waves of visible light. For this reason, infrared photographs often much clearer than ordinary photographs. Pictures can be taken with infrared rays even at night or in complete darkness.

** Uses of Infra-red in Law Enforcement**

1. Questioned documents. Even crossed-out words or writings on a charred piece of paper can be read if photographs of them are taken with infrared rays.   

1. Aerial photography.        

        a. Infrared photography can enhance the contrast of the terrain.      

b. Coniferous (darker) and deciduous (lighter) growth is differentiated.                    

1. Surveillance photography.  

1. Detection of gunshot-powder burns, stains and irregularities in cloth.    
2. Detection of certain types of secret writings.
3.  It can differentiate inks, dyes, and pigments that appears visually the same;
4.  Fabrics that appear to be similar but have been dyed differently can be identified by infrared;
5.  It may also reveal the contents of sealed envelopes;
6. It is also valuable in detecting stains on cloth, including blood stains that are not visible to the eye; and,
7. Powder residues surrounding bullet holes in cloth, even when the fabric is dark in color or bloodstained, may be made visible by infrared.

ULTRAVIOLET PHOTOGRAPHY

• Some materials will absorb ultraviolet, while others will reflect these radiations. Some have partial reflection. These effects can be recorded photographically suing ultraviolet radiation. Black-and-white films are sensitive to most wavelengths of ultraviolet. By using a filter that absorbs all visible light but passes ultraviolet, it is possible to make a photographic exposure with just ultraviolet.

**Uses of Ultra-violet in Law Enforcement**

a. Try ultraviolet photography after visible light techniques and infrared light techniques fail (questioned documents, etc.).

b. Fingerprints on multicolored surfaces (dust with fluorescent powder or ninhydrin).

c. Body secretions such as urine, semen and perspiration often glow when illuminated by ultraviolet light.

d. Money and other valuables can be dusted or marked to identify thief.

e. Photographing “invisible ink”.

PHOTOMICROGRAPHY

It combines a camera with microscope. Pictures can then be taken of things too small to be seen with naked eye.  A photograph taken through a microscope is called photomicrograph.

• The practice of photographing very small objects in order that they may be seen in comfort. (One should not confuse this with micro-photography, which is the opposite.)
• The practice dates from the earliest days of photography. The first known example is that of Fox Talbot who, using a solar microscope, had photographed an insect's wing, magnified some 15 times. John Benjamin Dancer also produced work in this field.

MACROPHOTOGRAPHY

 Photography of a subject where the image is recorded in the same or larger than actual size.