Forensic Photography - Lesson 1 PDF

FORENSIC PHOTOGRAPHY BY: CROMWELL G SANCHEZ  LESSON 1 UNDERSTANDING THE PHOTOGRAPHY  Photography » Is define as an art or science of reproducing images of objects by the action of Light on Sensitive Surface with the aid of image forming device and the chemical...

FORENSIC PHOTOGRAPHY BY: CROMWELL G SANCHEZ  LESSON 1 UNDERSTANDING THE PHOTOGRAPHY  Photography » Is define as an art or science of reproducing images of objects by the action of Light on Sensitive Surface with the aid of image forming device and the chemical process storage therein. camera *traditional digital- memory card » Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. With an electronic image sensor, this produces an electrical charge at each pixel, which is electronically processed and stored in » The result with photographic emulsion is an invisible latent image, which is later chemically "developed" into a visible image, either negative or positive depending on the purpose of the photographic material and the method of processing. » A negative image on film is traditionally used to photographically create a positive image on a paper base, known as a print, either by using an enlarger or by contact printing. » Photography is derived from the Greek words: » Literally speaking photography can be defined as to ‘write or draw’ with the aid of light. » Picture is derived from the Latin word pictura or pictus, which means to PAINT. » An image (from Latin: imago) is an artifact that depicts visual perception, such as a photograph or other two- dimensional picture, that resembles a subject—usually a physical object and thus provides a depiction of it.  History of Photography / Events and Personalities in Photography CAMERA OBSCURA (1700) » Latin camera obscūra, “dark chamber” » also referred to as pinhole image » A camera obscura device without a lens but with a very small hole is sometimes referred to as a "Pinhole Camera", although this more often refers to simple (home-made) lens-less cameras in which photographic film or photographic paper is  Leonardo da Vinci's Camera Obscura » The camera obscura was one of the most interesting optical inventions Leonardo worked with. » He was not the first person to use one of these, but he was first to notice the similarity between the way a camera obscura worked and the way the human eye functioned. » A camera obscura is merely a dark box (or even a very dark room) with a very small hole in one wall that lets in light. Directly across from the hole the image from the outside world will be projected onto the wall upside down. A diagram of a Camera Obscura with an upright projected image at the top.  Pinhole Camera. Light enters in a dark box through a small hole and creates an inverted image on the wall opposite the hole. LINK : How to Make Pinhole Camera with Poster Board - Bing video https://www.youtube.com/watch?v=Jp_cELoP3HU  Photograms (1800), Thomas Wedgwood and Humphry Davy » is a photographic image made without a camera. » It involves placing things on the surface of a light sensitive material and then exposing them to light. Traditionally this process has been done using photographic paper. » The technique is sometimes called cameraless photography.  A photogram of a number of photography- related objects LINK: Cyanotype photogram - Bing video  Heliography (1825) Joseph Nicéphore Niépce » Commonly known or referred to simply as Nicéphore Niépce, was a French inventor, usually credited as the inventor of photography. » A technique he used to create the world's oldest surviving product of a photographic process: a print made from a photoengraved printing plate in 1825. In 1826 or 1827, he used a primitive camera to produce the oldest surviving photograph of a real-world scene. One of the three earliest known photographic artifacts, created by Nicéphore Niépce in 1825. Niépce had managed to capture small camera images on paper coated with silver chloride. LINK:(39) The 1st Photographer - Joseph Nicéphore Niépce - YouTube  DAGUERREOTYPE Louis-Jacques-Mandé Daguerre » Better known as Louis Daguerre » French artist and photographer, recognized for his invention of the daguerreotype process of photography. » He became known as one of the fathers of photography. » For the process which was eventually named the daguerreotype, he exposed a thin silver- plated copper sheet to the vapour given off by iodine crystals, producing a coating of light-sensitive silver iodide on the surface. View of the Boulevard du Temple, taken by Daguerre in 1838 in Paris, includes the earliest known photograph. The image shows a busy street, but because the exposure had to continue for several minutes the moving traffic is not visible. LINK: The Daguerreotype - Photographic Processes Series  Sir John Frederick William Herschel » English polymath, mathematician, astronomer, chemist, inventor, experimental photographer who invented the blueprint, and did botanical work. » 1839, Herschel coined the term Photography, » which means light-drawing, or sun-writing from the Greek roots for ‘Photo' (light) and ‘Graph' (to draw). Herschel's first glass-plate photograph, dated 9 September 1839, showing the 40-foot telescope.  William Henry Fox Talbot » English scientist, inventor and photography pioneer who invented the salted paper and CALOTYPE processes, precursors to photographic processes of the later 19th and 20th window Latticed centuries. at Lacock Abbey, August 1835, a positive from what may be the oldest existing camera negative. LINK: Talbot's Processes - Photographic Processes Series (39) Talbot's Processes - Photographic Processes Series - Chapter 3 of 12 - YouTube  James Clerk Maxwell » Scottish scientist in the field of mathematical physics. » The first permanent color photograph was taken in 1861 using the three-color- separation principle first published by Scottish physicist James Clerk Maxwell in 1855.  Edwin Herbert Land » American scientist and inventor, best known as the co-founder of the Polaroid Corporation. » His Polaroid instant camera went on sale in late 1948 and made it possible for a picture to be taken and developed in 60 seconds or less. LINK: Polaroid: Edwin Land, Instant Photography and the SX-70  The Eastman Kodak Company » From the company's founding by George Eastman in 1888. » Kodak, is an American technology company that produces camera-related products with its historic basis on photography. » Kodak developed the first handheld digital camera in 1975 which is prototype.  DIGITAL CAMERA » 1988 Fuji Fujix DS-1P » First unveiled at the 1988 Photokina trade show in Köln Germany, Fujix DS-1P is considered as the first true digital camera. First commercially available D.C. » 1991 Kodak DCS-100 » In 1991, Kodak created the first-ever digital SLR. The Kodak Digital Camera System (DCS) was essentially a modified Nikon F3 whose film chamber and winder were modified to make room for sensors.  LASER » Is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" » Originated as an acronym for "light amplification by stimulated emission of radiation". » Makes the Holograms possible (Three Dimensional Image). LINK: How to make your own hologram How To Make Your Own 3D Hologram Projector - Easy DIY Tutorial - Bing video  LESSON 2 THE LIGHT AND THE PHOTOGRAPHIC RAYS  Light  Is a radiant electromagnetic energy that can be seen by the naked eye.  Scientifically, it can be define as an aspect of radiant energy of which a human observer is aware through the visual sensations which arises from the simulation of the retina of the eye.  Light Classification 1. Visible Light- those than can be detected by the retina of the eye. 2. Invisible Light/ Non- Visible- these are the Radiation which are either too short or too long on Wavelength to excite the retina of the eye.  Qualities of Light  The Velocity it Travel- this refers to the speed of light as it travels. Light Travels 186,000 miles per second or (300,000 kilometers), the speed of light in water is about 124,000 miles per second.  The Wavelength- the distance between two successive crest, since the light travels in wave motion.  The Frequency- refers to the number of waves passing in a given point in one second. Different Photographic Rays  X-Ray Radiation  Ultra Violet Rays  Visible Rays  Infra- Red Rays  X - Ray Radiation  Wavelength of.01 to 30 millimicron  Use in producing shadow photographic of internal structures of solid object.  Ultra Violet Rays Wavelength of 30 to 400 millmicron Use in photographing fingerprints in multi- colored background and documents that are altered chemically as well as detection of secret writing. Also known as black light  Visible Light Rays Wavelength of 400 to 700 millimicron Only within these wavelengths that the human eye is capable of perceiving. These produce white light. The Primary Colors of Light: 1. Blue- with 440-500 millimicron 2. Green - with 490-600 millimicron 3. Red- with 650-700 millimicron Violet- 400 to 440 nm Blue - 440 to 490 nm Green- 490 to 540 nm Yellow- 540 to 590 nm  A mixture of the Primary Colors of light produces its Secondary Colors of Light. 1. Cyan- combination of Blue and Green 2. Yellow- combination of Red and Green 3. Magenta- combination of Red and Blue  Sources of Light Natural Light Artificial Light Natural Light  Light produced without the intervention of man. The most common type of light is the Daylight, moon star, lightning, fire and other heavenly bodies. Intensity- means the amount or quantity of light that at the present scene.  Classification of daylight according to their intensity; Bright Sunlight- a lighting condition where objects in open space cast a deep and uniform and distinct shadow. Hazy Sunlight- Objects in open space cast a transparent shadow, clouds partially covers the sun. Dull Sunlight- objects in open space cast no shadow , sun is totally covered by the clouds. a. Cloudy Bright-objects to the far distance are clearly visible. b. Cloudy Dull- visibility of distant objects are already limited.  Artificial Light  Light source of this category is man- made and is divided into the continuous radiation and the short duration. Common Types of Artificial Light  Photo flood Lamp  Flash Bulbs- chemical  Fluorescent Light  Infra Red Lamp  Electronic Flash-electronic  Ultra Violet Lamp Photo flood Lamp Flash Bulbs- chemical Fluorecent Light Infra- Red Lamp Electronic Flash Ultra Violet Lamp  Bending Of Light  When travelling in open space, light travels in a straight line (186, 000/miles per second).  However, when light contact with an object, it may be bended in the following manner. Reflection- it bounces of, in all directions due to the microscopic irregularities of the interface. Refraction- it is the change in direction of a wave due to a change in its speed. This is commonly observed when a wave passes from one medium to another. Diffraction- it is described as apparent bending of waves around small obstacles and the spreading out of waves past small openings. It also describe as the bending of light when it hits a sharp edge of an opaque object. Kinds of Object on how they Behave on Light Transparent Object- allows sufficient visible light to pass through them that the object on the other side maybe clearly seen. Translucent Object- allows light to pass, however diffuse it sufficiently that objects on the other side may not be clearly distinguished. In some cases the objects on the other side may be recognizable but sharp detail and outlines are obscure. Opaque Objects- so greatly diffuse the light that recognizing the object on the other side is very difficult if not possible.  Lesson 3 HE CAMERA AND ITS PARTS  Camera Is a light tight box with a pinhole or lens form an image, with a shutter and diaphragm to control time and amount of light passing through it and a means of holding a sensitized material to record photographic image.  Pentapri sm The Camera and the Human Eye  Parts of Camera  Light Tight Box (Body of the Camera)- it is an enclosure devoid of light. The lens ( like a barrel of a gun)- a transparent medium which either converge or diverge light rays passing trough it. Is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. Shutter- A contraption device that opens to uncover the film to make an exposure in pre- determined interval of time. Is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or light- sensitive electronic sensor to light to capture a permanent image of a scene. Focal Plane Between-the-Lens- Shutter Shutter Film Holder or Holder of Sensitized Material- located at the back of the camera and the main function is to hold the film  Types and Classification of Lenses Types of Lenses Convex lenses-(sometimes called a positive lens), the glass (or plastic) surfaces bulge outwards in the center giving the classic lentil-like shape. A convex lens is also called a converging lens because it makes parallel light rays passing through it bend inward and meet (converge) at a spot just beyond the lens known as the focal point.. Convex lenses are used in things like telescopes and binoculars to bring distant Concave lens- is exactly the opposite with the outer surfaces curving inward, so it makes parallel light rays curve outward or diverge. That's why concave lenses are sometimes called diverging lenses.  (One easy way to remember the difference between concave and convex lenses is to think of concave lenses caving inwards.)  Classification of Lenses Wide Angle Lens- Usually use on non- spacious or narrow places or areas mostly on small rooms. 35 mm below. Normal Lens- this provides realistic view of the scene to be photograph. 35-69mm. Telephoto Lens- great magnification and mostly use for surveillance purposes for its capability to take picture even a great distance.70 up mm. Zoom lens- a lens with variable focal length.  Inherent Lens Defects or Aberrations Spherical aberration- is a type of aberration found in optical systems that use elements with spherical surfaces. Lenses and curved mirrors are most often made with surfaces that are spherical, because this shape is easier to form than non-spherical curved surfaces. Light rays that strike a spherical surface off-centre are refracted or reflected more or less than those that strike close to the centre. This deviation reduces the quality of images produced by optical systems. On top is a depiction of a perfect lens without spherical aberration: all incoming rays are focused in the focal point. The bottom example depicts a real lens with spherical surfaces, which produces spherical aberration: The different rays do not meet after the lens in one focal point. The further the rays are from the optical axis, the closer to the lens they intersect the optical axis (positive spherical aberration). Astigmatism- is one where rays that propagate in two perpendicular planes have different focus. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances. Comatic aberration- is an optical system refers to aberration inherent to certain optical designs or due to imperfection in the lens or other components that results in off-axis point sources such as stars appearing distorted, appearing to have a tail (coma) like a comet. Specifically, coma is defined as a variation in magnification over the entrance pupil. In refractive or diffractive optical systems, especially those imaging a wide spectral range, coma can be a function of wavelength, in which case it is a form of chromatic aberration. Distortion is a deviation from rectilinear projection; a projection in which straight lines in a scene remain straight in an image. It is a form of optical aberration. Chromatic aberration (CA), also called Chromatic Distortion and Spherochromatism Is a failure of a lens to focus all colors to the same point.It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength.  The Lens Diaphragm/ Aperture The aperture, sometimes called the diaphragm or iris, is the opening through which light enters the camera. Typically located in the lens,this opening can be widened or narrowed to control the amount of light that strikes the film. The size of the opening is set at standard increments, typically called "f- stops" (but also "f-numbers", "stop numbers", or simply "steps" or "stops")  F# (F number) is often used in photography to describe the aperture. The ff. Are the f-number series: F1.4- F2- F2.8- F4- F5.6- F8- F11- F16- F22 etc.  Shutter Is a device that allows light to pass for a determined period, exposing photographic film or a photosensitive digital sensor to light in order to capture a permanent image of a scene. The shutter is constructed so that it automatically closes after a certain required time interval.  Kinds of Shutter Central Shutter or Between the Lens Shutter Is not a type of shutter as such, but describes the position of the shutter: it is typically a leaf shutter (or simple leaf shutter), and located within the lens assembly where a relatively small opening allows light to cover the entire image. Leaf shutters can also be located behind, but near, the lens, allowing lens interchangeability. The alternative to a central or behind-the-lens shutter is a focal-plane shutter. Focal- plane Shutter- is positioned just in front of the film, in the focal plane, and moves an aperture across the film until the full frame has been exposed. Focal-plane shutters are usually implemented as a pair of light-tight cloth, metal, or plastic curtains.  Shutter Speed Shutter Speed or Exposure time is the length of time when the film or digital sensor inside the camera is exposed to light, also when a camera's shutter is open when taking a photograph. The amount of light that reaches the film or image sensor is proportional to the exposure time. Like f- number series, shutter speeds also change in each step, so each longer time doubled the proceeding step. 1- 2- 4- 8- 15- 30- 60- 125- 250- 500- 1000..… Two other settings in making very long exposures B (for bulb) keeps the shutter open as long as the shutter release is held.  LESSON 4 THE TYPES OF CAMERA AND ITS ACCESSORIES  Types of Camera ü Box Camera Were introduced as a budget level camera and had few if any controls. The original box Brownie models had a small reflex viewfinder mounted on the top of the camera and had no aperture or focusing controls and just a simple shutter. ü Rangefinder Camera A lens technology developed and wide aperture lenses became more common, rangefinder cameras were introduced to make focusing more precise. ü Single-Lens Reflex (SLR) Camera Single-lens reflex camera (SLR) is provided with a mirror to redirect light from the picture taking lens to the viewfinder prior to releasing the shutter for composing and focusing an image. ü Twin-lens reflex camera Twin-lens reflex cameras used a pair of nearly identical lenses, one to form the image and one as a viewfinder. Parallax errors were encountered and some cameras also included an indicator to show what part of the composition would be excluded. ü Instant Camera After exposure every photograph is taken through pinch rollers inside of the instant camera. Thereby the developer paste contained in the paper 'sandwich' distributes on the image. ü Digital Cameras A digital camera (or digicam) is a camera that encodes digital images and videos digitally and stores them for later reproduction. ü Camera Phone In 2000, Sharp introduced the world's first digital camera phone, the J-SH04 J-Phone, in Japan. By the mid-2000s, higher-end cell phones had an integrated digital camera. By the beginning of the 2010s, almost all smartphones had an integrated digital camera. Parallax- is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.  Camera Accessories ü Tripod Is used to stabilize and elevate a camera, a flash unit, or other photographic equipment. All photographic tripods have three legs and a mounting head to couple with a camera.  Flash Units Is a device used in photography producing a flash of artificial light. A major purpose of a flash is to illuminate a dark scene. Other uses are capturing quickly moving objects or changing the quality of light.  Types of Flash Flash-lamp/Flash powder   Studies of magnesium by Bunsen and Roscoe in 1859 showed that burning this metal produced a light with similar qualities to daylight.  Flashbulbs  The use of flash powder in an open lamp was replaced by flashbulbs; magnesium filaments were contained in bulbs filled with oxygen gas, and electrically ignited by a contact in the camera shutter. Electronic Flash  The electronic flash tube was introduced by Harold Eugene Edgerton in 1931; he made several iconic photographs, ü Light Meter Is a device used to measure the amount of light. In photography, a light meter (more correctly an exposure meter) is used to determine the proper exposure for a photograph. -4,-3,-2,-1,0,+1+2+3+4 ü Cable Release A remote shutter button that can be connected to the camera via a cable to remotely control the shutter, it can be used to lock the shutter open for a desired period of time. It is also commonly used to prevent camera shake from pressing the built in camera shutter button.  Photo Filters In photography and cinematography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The filter can be of a square or oblong shape and mounted in a holder accessory, or, more commonly, a glass or plastic disk in a metal or plastic ring frame, which can be screwed into the front of or clipped onto the camera lens.  Filters modify the images recorded. Sometimes they are used to make only subtle changes to images; other times the image would simply not be possible without them.  Types of Photo Filters Correction Filter/ Light Balancing Filter Light Balancing Filters correct artificial lighting so colors appear more natural.  Contrast Filter  Used to change relative brightness, so that all colors will better contrast or different degree of brightness.  Haze Filter/UV Filter Nowadays UV filters are primarily used to protect the front element of a camera lens since they are clear and do not noticably affect the image. With film cameras, UV filters reduce haze and improve contrast by minimizing the amount of ultraviolet (UV) light that reaches the film. Neutral Density Filter A neutral density filter (ND filter) is a filter of uniform density which attenuates light of all colors equally. Polarizing Filter This reduces oblique reflections from non- metallic surfaces, can darken the sky in colour photography (in monochrome photography colour filters are more effective), and can saturate the image more by eliminating unwanted reflections.  PROBLEMS WITH LENS FILTER Filters should only be used when necessary because they can also adversely affect the image. Filters may also introduce physical vignetting (light fall- off or blackening at the edges of the image)  LESSON 5 THE SENSITIZED MATERIAL/DEVELOPMENT MATERIALS AND FILM APPLIED TO FORENSIC PHOTOGRAPHY  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 the Sensitized Material 1. Emulsion = is that part of the film or photographic paper which contains the silver grains which is the one 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 prevents halation. 3. Base = Support the emulsion.  FILM Film consists of a photosensitive compound known as Silver Halide (AgX), which reacts with light. The first flexible photographic roll film was marketed by George Eastman, founder of Kodak in 1885, but this original "film" was actually a coating on a paper base. Types of Film According to Use 1. Black and White Film- usually represented by a prefix or asuffix “Pan” or “Ortho” and generally used in black and white photography. 2. Colored Film- can be divided into two: the Negative type and the reversal type of colored film.  According to Spectral Sensitivity Spectral sensitivity- is the responsiveness of the film emulsion to the different wavelength of the light course. 1. Blue – Sensitive film - sensitive to U.V. light and Blue Color. 2. Orthochromatic Film = Sensitive to U.V. Light up to the green. 3. Panchromatic film = Sensitive to U.V. Light up to red (sensitive to all colors of the visible light) 4. Infra-red Film- Sensitive to all colors and to infra-red light. A. FILM SPEED (Emulsion Speed) This refers to the degree of sensitivity of the film to light. 1. ASA (American Standards Association)- this is expressed in arithmetic value system. The bigger the number the more sensitive the film is. ASA 12, 25, 50, 100, 200, 400, 800, 1600 2. DIN ( Deutche Industre Normen)- expressed in Logarithmic value system.Used in the same principle as the ASA Din 12, 15, 18, 21, 24, 27, 30, 33 etc. 3. ISO (International Standard Organization)- expressed as combination of ASA and DIN rating.  Photographic Paper A paper coated with a light-sensitive chemical formula, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a visible image; with most papers the image density from exposure can be sufficient to not require further development, aside from fixing and clearing, though latent exposure is also usually present. The light-sensitive layer of the paper is called the emulsion.  Types of Photographic Papers According to Emulsion Used (Silver halides content) 1. Silver Chloride paper- used for contact printing, the size of the positive print is the same as the size of the negative used. Sensitivity to light is low and give blue-black tones when properly developed. 2. Silver bromide paper- used in projection, printing and enlarging process. Most ideal paper used in police photography.Will give black tones when properly developed 3. Silver Chlorobromide Paper- used for both projection and contact printing slow emulsion. 4. Variable Contract Paper - combines the contrast range in one paper uses a special chlorobromide emulsion that produces varying contrast responses upon exposure to different colors of light  According to Physical Characteristics Weight 1.1 Light Weight- designed for high flexibility and when paper thickness is not of consideration intended for purposes which involved folding. 1.2 Single Weight- used for small prints or which are needed to be mounted on solid fine details necessary in the production used in ordinary photographic purposes 1.3 Double Weight- generally used for large prints because they stand up under rough treatment.  1. Surface Texture Glossy- designed for fine details and brilliant image formation. 2. Semi-matte Paper- obscure fine details. 3. Rough Paper- used for large prints or where breath rather than detail is necessary. 4. Color White Paper- better used in police photography. 5. Cream Paper- preferred for pictorial effect, portraits, landscapes or where warmth effect is desired. 6. Buff Paper- paper for tone prints.  According to Contrast 1. Velox No. 0- Used for printing extremely contrast negative or expremely exposed film 2. Velox No. 1- Used for high contrast negative or over exposed film 3. Velox No. 2- Used for normal exposed film 4. Velox No. 3- Used for negative with weak contrast or underexposed film. 5. Velox No. 4- Used to provide sufficient contrast to compensate for very thin or weak negatives, useful imprinting if high contrast is desired. 6. Velox No. 5- For flat negatives that are unprintable.  Lesson 6 THE CHEMICAL PROCESS  Photographic Processing or Photographic Development Is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.  CHEMICAL PROCESS- refers to the process of making latent photographic image visible and permanent. ü Development Typical developer is made up of four different components: the developing agent, the accelerator, the restrainer, and the preservative.  Stop- Bath Halts the developing process to prevent the developing agent from reducing all the grains of silver halide,  Fixation   Fixer is to dissolve the unreduced silver halide molecules left on the paper after development. This is a way of preserving the image because if these grains are not removed, they can continue to be reduced by sunlight and degrade the image.  Developing a Film in a Darkroom Step 1: Materials and Set Up The first step in preparing to develop film is to set up your workspace and gather all materials required. Do this before turning the lights off since you’ll need complete darkness once the development process begins. You’ll need the following materials: Film reel Film tank Cassette openerScissors Thermometer Timer Plastic container Clothesline or wire rack Clothespins or clips Paper towels Plastic sleeves Film developer Stop bath Fixer Wetting agent Step 2: Open Film Cassette Do not open your film until you are in complete darkness as exposing your film to even the tiniest level of light can destroy your negative. To open the film cassette, hook the edge of the lid under the cassette opener, then bend it to the side until the lid pops off. Step 3: Cut Film Off Cassette with Scissors Take your film out of the cassette and cut it off with scissors. To do so, unroll the film until you reach the small plastic cassette in the center, then cut through the film where it connects with the piece of tape that secures the film to the plastic. You may have to feel around for this since it will be dark. Step 4: Load Film Onto Reel To load the film onto the reel, begin by finding the slit on the edge of the reel and slide the film into it. Once secure, twist the side of the reel back and forth to wind the rest of the film. You’ll know it’s finished when all the film is securely wrapped around the reel. Step 5: Place Reel in Film Tank Locate your film tank’s detached core, and slide it through the hole in the center of the film reel. Next, place the reel flat in the bottom of the tank so that the core is sticking up in the center. Cover your film tank with the lid and make sure it’s secured tight. This is where it will remain for the rest of the development process. Step 6: Create Developer Mixture Since your film is safe in your film tank, you can now turn on the lights to complete the next steps. The developer mixture is used to develop film negatives in the tank, and while the exact amount will vary depending on the size of the film tank, it’s usually around sixteen fluid ounces of film developer mixed with sixteen fluid ounces of water. Mix the two ingredients in a metal or plastic container, not in the film tank itself. Step 7: Measure Temperature of Mixture It’s vital to measure the temperature of your mixture to determine how long your film will need to develop. All film is different, and you can find developing times online or in the manufacturer’s instructions. Typically, film needs 8–11 minutes to develop properly. Step 8: Pour Mixture into Film Tank You should see a lid on the uppermost part of your film tank. Be sure you are unscrewing this lid, and not the larger lid that is housing the film and sealing the tank shut. Pour the mixture directly down the funnel-shaped hole. Once the entirety of the mixture is poured in, immediately set a timer for the time you determined in step seven. Step 9: Agitate Film Periodically As the film develops, you’ll want to agitate it— continuously turn the tank to help spread the developer around —periodically throughout the timed interval. It’s recommended that you use the following schedule when agitating: · First minute: Agitate the film for 30 seconds. Place your tank on a flat surface for 20 seconds, then agitate again for the remaining 10 seconds. · Second minute: Let the film rest for 50 seconds, then agitate for the last 10 seconds. · Remaining minutes: Repeat as you did the second minute for the rest of the minutes until finished. Step 10: Fill Tank with Stop Bath Stop bath is a liquid chemical mixture that prevents film from developing any further. To use it correctly, first drain the developer mixture from the film tank. Replace it with stop bath until tank is full. Agitate for 30 seconds to help the stop bath spread evenly throughout the tank. Step 11: Fill the Tank with Fixer The final chemical used in the development process is fixer, which is used to help stabilize film so that it can be exposed to light without damage. Pour out your stop bath and replace it with the fixer. Follow the same agitation schedule you used with the developer mixture, leaving the fixer in the tank for about 3–5 minutes. Step 12: Rinse and Soak Film After using fixer, your film reel is safe to remove from the tank. Thoroughly rinse the film with cold water for a few minutes to ensure they are no leftover chemicals. Next, soak your film in a wetting agent to help rid it of excess water and avoid developing streak or bubble marks. Step 13: Hang Film to Dry Take your film off the reel and unroll it by twisting the sides of the reel in opposite directions. Then pull it apart, separating it into two pieces. Use a clothespin to hang the film to dry, and attach another to the bottom of the film so that it hangs taut. Let it dry for several hours before removing. Step 14: Clean and Store Film Remove any excess streaks with a cleaner. It’s advised to cut the film five smaller strips of negatives so that you can easily slide them into a plastic sleeve. Sleeves provide protection, keeping negatives moist and free of smudges or debris. Leave them covered until you’re ready to develop your film. From here, you can move on to the printing process. A. Paper Printing/ Photographic Finishing In order to get a “positive” final print, the negative must be projected onto photographic paper. Two (2) basic “finishing” methods: 1. Contact Printing 2. Enlargement/ Reduction Printing CONTACT and ENLARGEMENT/REDUCTION In order to get a positive final output, the negative is then printed to a photographic paper. A negative image exposed to a negative paper results in a reversal of lightness, meaning a positive image. Contact Printing Negative Photographic Paper , A CONTACT print: There are several methods of making a final image. The simplest is called contact printing, where the negative is placed directly on top of the photographic paper. The main difference between photographic film and paper is the base- film uses plastic, and paper uses - paper. Then the paper is exposed with light, under proper exposure. The paper is then processed just like the film was. Enlarger / Reducer Light Negative Photographic Paper The second method is utilizing an enlarger. Often, the film size is smaller than the desired print size (35mm film is little over 1.5 inches!) The enlarger images the negative onto photographic paper, and depending on the optic setup, the image can be enlarged, or reduced. The exposed paper is then processed to yield a final image.Optics are used to produce an image of the negative on photographic paper.  Lesson 7 FORENSIC PHOTOGRAPHY/ CRIME SCENE PHOTOGRAPHY AND ITS APPLICATION  Forensic Photography/ Crime Scene Photography Forensic photography, also referred to as Crime Scene Photography, is an activity that records the initial appearance of the crime scene and physical evidence, in order to provide a permanent record for the courts. Crime scene photography differs from other variations of photography because crime scene photographers usually have a very specific purpose for capturing each image.  Crime scenes can be major sources of physical evidence that is used to associate or link suspects to scenes, victims to scenes, and suspects to victims. Anything found at a crime scene can be physical evidence. In scientific crime scene investigation, the first activities at the crime scene are essential for the successful preservation of the physical evidence. The first responder and ultimately the crime scene investigator have the obligation to make the scene secure and ensure that any further activities at the scene do not change the evidence. Features in Crime Scene Photography Common photography related to creative and artistic photography often shows their results in a different way. Creative and artistic photographs are perfectly fine. However, the forensic photography is different. They should serve several purposes. For people who were at the original crime scene, forensic photos will help refresh their memory as time goes by. People who could not be present at the original crime scene, it provides them with the opportunity to see the crime scene and the evidence within the crime scene.  The forensic photos can be utilized by law enforcement professionals who will become involved with crime and will be utilized later when the crime case goes to trial. Judge, jury, attorney and witnesses can reuse and utilize forensic photos for lawful evidence or references. Sometimes, forensic photos can be the only way to collect lawful evidences; therefore, two key points are important:  Documentation of the crime scene and the evidence within the crime scene.  Collection of evidence. These images can then be later used as examination-quality photographs by experts/analysts from the forensic laboratory.  The Crime Scene is search for the physical evidences (visible or invisible). There are various types of search methods employed by the investigating officers and the forensic scientists at the scene of crime. The searching methods mainly depends on: Type of Crime (Rape, murder, burglary, theft, etc.) Nature of Crime (Homicide, suicide, or accident) Size of the crime scene (macroscopic or microscopic) Location of the crime scene (indoor, outdoor, combination of indoor or outdoor, or any remote area like underwater, desert, etc.) Complexity of the crime scene Following are the basic search methods, usually commissioned on the crime scene: 1. Zone Method 2. Strip Method 3. Line Search 4. Grid Method 5. Spiral Method (Outward Spiral & Inward Spiral) 6. Wheel Search Method 7. Random Search Zone Method In this method the crime scene is virtually divided into different zones. The number of zones depends upon the size and complexity of the crime scene. This method can be applicable to both indoor and outdoor crime scenes. Different people will be employed in individual zones, and will search their zones thoroughly for the evidences normally as well as using different techniques. After searching in their own zones, the zones will be exchanged to check the accuracy and double check for any missing items. This method cannot be applicable on very squeezed and complex crime scenes like elevators, lift shafts, or stairs. Strip or Parallel Method In this method the virtual strips or line are being imagined to walk through on the crime scene and look for the evidences. The method is well suited for the crime scene like class rooms, where rows are present already, each row can be considered as a strip. Also, minimum number of the personals are required for this method. One person will start the walk through from one corner of the strip and will move towards the other looking for the evidences. The walk through should be slow and thorough. If two personals are employed, then each of them can start from two different points and continuing to the different ends to double check the search. Grid Method (two parallel strip) It is just like the strip method; the only difference is that two strips are considered to form a grid. Again, only two people can do the searching walking through on separate strips and then will switch their strips for the more accuracy. It is a good method for large indoors and outdoors crime scenes. Spiral Method This is well suited for lager indoor and outdoor crime scene with less obstacles (like furniture etc.). The searcher will start either from the center of the room (outward) or from the periphery (inward) search as show in the images below. Also, two investigators can search together, one moving from the center towards the periphery and other one vice versa. Wheel Search Method This method is only applicable to the lager outdoor scenes like fields, desert, or other such open areas. It is like the zonal method; however, the wheel is divided into various zones depending upon the size of the crime scene. Different individuals will be employed in separate zones and then switching their zone for more accuracy. The investigators or the searchers can begin from the epicenter moving towards their zones to complete the search, and then returning back to the epicenter for the discussion or collection procedures. Levels of Searches First Level: search at the scene of crime Second Level: through photographs, sketches, witnesses, relatives, and other sources Third Level: Revisit the crime scene if possible, Interrogation etc. Evidence Removal: The investigator or the forensic expert has to be sure to document each and every evidence encountered at the particular scene. The evidences should only be removed after proper documentation (photography/videography/sketching/notes), and then should be properly collected in appropriate containers. Crime Scene Evidence Crime scenes are the source of the physical evidence that is used to associate or link suspects to scenes, victims to scenes, and suspects to victims. Any item found at a crime scene can be physical evidence; it can be labeled as the debris of criminal activity. There is considerable overlap among identifications, but evidence can be categorized into the following broad groups based on its origin, composition, or method of creation: Biological evidence - any evidence derived from a living item. Includes physiological fluids, plants, and some biological pathogens. Chemical evidence — any evidence with identifiable chemicals present. Patterned evidence — any evidence with a pattern or predictable pattern of appearance. Trace evidence — any evidence of such a small size so  In addition to identifying the type of physical evidence found at a crime scene, it is necessary to obtain valuable investigative information from the analysis of the items of physical evidence. Determination of corpus delicti — the evidence is used to determine if a crime has taken place. Modus operandi identification — criminals repeat behavior. Repeated methods of entry, for example, by kicking in a back door with the same shoe leaving the same footwear impressions throughout the crime scene. Association or linkage — the Locard Exchange Principle — transfer of evidence by contact. Disproving/supporting victim/suspect/witness statements — the evidence may or may not support what these groups say. Identification of suspects/victims/crime scene location — fingerprints and even DNA can be used to identify who was present at a crime scene. Provide for investigative leads for detectives — Essential Steps in Crime Scene Photography The first activities at the crime scene are essential for the successful preservation of the physical evidence. First Responders The crime scene investigator is rarely the first person at a crime scene. Most first responders work on reflex or instinct at the scene. Their tasks are to save lives or apprehend suspects. Unfortunately, that may mean that physical evidence may be inadvertently altered, changed, or lost due to the actions of a first responder. The crime scene investigator needs to communicate with the first responders to determine if any changes or alterations have occurred at the scene before the scene investigator arrived. Crime Scene security Locard's exchange principle is the basis for the use of physical evidence in a criminal investigation, it is extremely important for the crime scene to be made secure and restrict the access to the crime scene by nonessential people. Many agencies allow easy access to crime scenes by anyone in the agency. Most media persons are kept out but changes to the scene and evidence can change in attempts to protect victims. Preliminary Scene Survey The preliminary scene survey or walk-through is the crime scene investigator’s first opportunity to view the target area crime scene. A simple visual search for obvious physical evidence can be accomplished Types Of Photographs to be Taken at the Crime- Scene Long Range or General View Photographs- as the name implies, capture the global aspects of the crime scene. Their purpose is to show exactly where the scene was, to the exclusion of any other location, and to show all boundaries of the scene. These photographs are typically taken in an overlapping fashion from the outside of the perimeter looking in, and from the center of the scene looking out, covering all areas of the scene. Items of evidence and their spatial relationships may be visible, but they are not the main subject of the photograph. Medium Range or View Photographs- transition of the viewer from an “outsider looking in” perspective to a more involved perspective. Items of evidence and their spatial relationships are shown, typically by depicting a single item in relation to a fixed object in the scene. Done correctly, this technique will show proper context, perspective, and scale. It will also show the precise position of each item of evidence. Close up Range or View Photographs- are deliberate depictions of individual items of evidence. They must show all sides of the item and clearly show any markings, defects, or other identifying features. Each photograph is usually taken twice: once with a scale, and once without a scale. The item must fill the frame of the camera. Shadows must be eliminated unless they are intentional. Extreme close up- This shot is not normally done in the crime scene. This view is to show the details of each or every evidence, to show minute objects or clearer view of the characteristics of the evidence. Fingerprint Photography The most common form of evidence collected at crime scenes is fingerprints. Fingerprints should be photographed before they are collected on major cases or if the latent may be destroyed when lifting. Occasionally, a latent print can be visible or developed on a surface but cannot be lifted (e.g. a fingerprint in blood). In such a case photographing the latent is the only way to document the evidence. Normal black–and–white High contrast film was used to film was used to photograph the same faint, photograph this faint, dusted fingerprint. dusted fingerprint. Fingerprint on drinking glass using transmitted lighting — position a diffused light source behind the glass. Questioned Document Examination Photography Questioned document examination (QDE) is a forensic science discipline pertaining to documents that are potentially disputed in a court of law. The examination’s primary purpose is to provide evidence about suspicious or questioned documents using a varietyMethod used principles of scientific by forensic experts and in methods. photographing questioned Document is the Low Angle Light & Photography. Firearm Identification using Comparison Microscope and Photography Firearm Identification is a comparative science that applies a two-level approach, using class characteristics and individual characteristics. Class characteristics of firearm barrels include measurable features which are part of the design of the firearm, such as the caliber and rifling pattern.  The class characteristics for a fired cartridge case include the cartridge caliber, the shape of the firing pin, and the tooling marks on the breech.  If there is sufficient agreement between the microscopic marks produced by the firearm and the marks observed on the evidence, then an identification can be made.