Part 7 The Course

Photography the taking and processing of film to produce a picture made by the chemical action of light on sensitive film and then made visible by chemical treatment.

In our modern society, photography performs a vital aspect in our interpretation of the environment and the way we lead our lives. It is paramount that all levels of commerce and industry utilize the benefits of photography to convey their products and image.

Photography began with the discovery of a practical light-sensitive chemical for recording the image formed in the camera. This chemical being "metal silver" "Silver halides" which are compounds of salts of silver like silver bromide, silver iodide and silver chloride will break down under the action of light to form tiny grains of black metallic silver. It can some times take light a long time to decompose sufficient silver halides to form a visible image. When the photographic film which is an emulsion (consists of a suspension of silver halides in thin layer of gelatine) and a transparent cellulose polyester or acetate are exposed to light. The silver halide crystals are amplified millions of times by development using chemicals able to increase the silver in light - struck areas. The light forms black silver and the camera image is recorded in negative tones - high lights black and shadows white. A chemical agent called a developer (usually metol or hydroquinone) assists the metallic silver halides to form in areas exposed to light. Lots of particles are formed under intense exposure and a few under weak exposure. A negative image is produced as a result of the tonal values being reversed. This is to say that the area's in the photographic scene that where dark appear light.

The two fundamental principals to photography are therefore chemical and physical. The primary chemical principal being the sensitivity of silver halides to light. And the physical principal being the physics of light. Light includes a wide range of electromagnetic radiation such as gamma rays, x-rays, ultraviolet rays and infrared.

Photographic film:- depends on the way in which each will react with different wavelengths of light. Late black and white film were only sensitive to shorter wavelengths of light. As photographic technology developed coloured dyes were added to the emulsion to make the silver halides more responsive to light of different wavelengths. Panchromatic:- Photographic emulsion sensitive to all colours of the visible spectrum and to a certain amount of ultraviolet light. This type of film is able to produce the whole range of colour tones. Orthchromatic:- is an emulsion which is sensitive to blue and green light, but which is insensitive to red. Chromogenic film:- Colour photographic material which forms dyes during processing rather than silver halides in the emulsion (from the oxidation products of development and colour couplers).

Instant picture material as introduced to the photographic world by the Polaroid Corporation in the 1940's revolutionised the way in which photographs were taken, using a hand held camera with a special designed self contained chamber. This enabled a contact size print to be produced in minutes of exposure. The exposed emulsion is brought into contact with a receiving paper, with a jelly -like layer of chemicals spread between the two. A negative black image is produced, and then a silver halide solvent encourages the transfer of silver from unexposed areas to the receiving paper, forming a positive print, positive and negative are peeled apart and the negative is thrown away. Light, exposure and composition can all be altered immediately.

Colour film:- are designed to produce a whole range of colour tones as colour. The subtractive colour process in which the three primary colours, yellow, magenta and cyan are combined to produce a full range of colours. This type of film consists of three silver halide emulsions on a single layer. The bottom which registers red, the middle which absorbs greens but not red and the top which is a yellow filter blocks blues and allows the transmission of green and reds. When light is exposed to a colour film, latent black and white images are formed on each of these three emulsions. As the process occurs the developer creates metallic silver images. This developer joins together with the dye couplers in each emulsion to magenta, yellow and cyan. The film is then bleached and the result is a negative image in primary colours.

Film speed is classified by format and speed. The speed of the film is denoted by the degree of sensitivity of the emulsion. This estimates under normal lighting conditions the amount of exposure required to photograph a subject. The manufacturers of such film will assign a standard numerical rating in which low numbers relate to a slow emulsion and high number refer to fast emulsions. Various systems are used to correlate the sensitivity of film. ISO International standardization organization is commonly used, by doubling the speed is denoted by doubling of the number. The DIN Deutsche Industries Norm is denoted by the doubling of speed by a rating increase of three. Film is classified slow if it has an ISO rating of about ISO 25/15 to 100/21.Its sensitivity is due to two factors. First the silver halides are very small and secondly the emulsion may be thinly coated to improve resolution. Photographs taken with a lower speed appear less grainy when enlarged thus as a result of there small silver halide grains. The image will have greater resolution and a finer appearance with loads of tones and sharpness in clarity. The ISO 100 and 200 (125/22 to 200/24) are classified as medium. This type of film permits greater exposure latitude, and represents a good compromise between light sensitivity and fine grain. Film in the ISO classification ISO 200/24 are considered fast, this is as a result of an increase in the concentration of silver halides crystals in the emulsion. By modifying the crystals and altering their structure to increase surface area, one also increases the speed. However; grain is likely to occur in enlargements, emulsion contrast is much lower than with normal or slow film. Ultra-fast film with an ISO rating higher than 400/27 or ISO 1600 include those with the fastest emulsion. In recent years photography has seen the development of the DX coding. DX cartridges of 35 mm film are assigned an electronic code that automatically tells the camera the ISO rating and then the number of frames on the roll. Modern electronic cameras are automatically equipped with this technology so as to adjust exposure.

Exposure range:- This is the latitude and range of exposure. Latitude:- the degree by which exposure can be varied and still produce an acceptable result The degree depends on the emulsion type. Fast films tend to have greater latitude than slower films.

Exposure:- this is the product of the intensity of light and the time the light is allowed to act on the film. Over-exposure:- term used to indicate that the light sensitive material has been excessively exposed. This can be as a result of light that is either too bright, or has been allowed to act too long resulting in a loss of sharpness, contrast and an increase density "greyness". Under-exposure:- the result of too little exposure in the camera. Resulting in not enough silver crystal halides for a correct interpretation of the shadows and dark area's.

Before the discovery of photographic materials, a dark chamber optical system existed. This system used a pinhole or a lens to project an image onto a screen. This was known as the:- Camera obscura. The development of the lens assisted in sharpening the overall clarity of the image, and film exposed in a controlled made it possible for a photographer to reproduce the image.

The basic modern camera consists of four components:-

Body:- (Within the body of the camera, there is a chamber in which film is held and exposed),

Shutter:- (system used to control the time that light is allowed to act on sensitive emulsion),

Diaphragm:- (the adjustable aperture behind or in front of the lens. The diaphragm controls the amount of light passing into the camera and lens)

Lens:- (Optical element made of glass or plastic and capable of bending light. A lens allows an object at a distance to be photographed in a clear sharp focus).

Focal plane shutter:- This lies just in front of the focal plane, consisting of a system of metal blades. A Slit travels across the image either vertically or horizontally and the film is exposed as the shutter blinds move across it.

Leaf shutter:- the is a system of meshed blades which spring apart to allow exposure under a given speed and duration.

Exposure control:- Click here This will give you a better insight, This is the total amount of light that is able to reach the light sensitive film. This is dependent on the brightness of the image, the camera aperture and the length of time for which the film is exposed. The Aperture and Shutter speed work in conjunction with one another. f numbers on the lens barrel indicate the size of the aperture relative to the focal length of the lens. f numbers are calculated by dividing the focal length of the lens by the diameter of the aperture i.e. 55 mm lens with an aperture of 5 mm = f11. Thus all lens stopped to the same f number will transmit the same amount of light. The aperture and diaphragm also control the Depth of field:- ( area of acceptable sharpness extended in front of and behind the object which is being focused on by the lens, usually expressed as one third of the distance in front and two thirds behind the point of focus. By widening the aperture this will cause the depth of field to decrease. In order to maximise the sharpness of the scene, back ground and fore ground a slow shutter speed and small aperture are used.

The design and structural components of the modern camera are very much under the same principal of the pin hole camera, take a few modifications. The view camera (large format standard camera, which has a ground glass screen at the back plane for viewing and focusing before film is inserted. The back and front are attached by a flexible bellow unit for flexibility and movement) which is predominantly used by professionals.

Rangefinder cameras:- Measures distance and runs in conjunction with the focusing mechanism of the lens. Displaying two images, showing a scene from two slightly different viewpoints a parallax, which will require for it to be superimposed to establish the measurement of distance. Mostly used by photojournalists because of its compact size.

Reflex cameras:- the two common ones used today are the SLR Single -lens reflex camera (a system of mirrors show the photographer the image precisely as the lens receive it). An attached mirror reflects the image onto a viewing screen, where the image is focused and composed. As the shutter is released, the mirror flips out of the light path while the film is exposed. Most state of the art SLRs have focal plane shutters, built in light meters, automatic exposure control and auto focusing with apertures which can be controlled manually or electronically. Most modern SLR cameras use a central control unit and electronics to automatically adjust the distance between subject and camera to get the correct exposure. This is either done by an infrared light beam which bounces off the subject to estimate distance and focus. The ultra modern camera uses a system of passive auto focus by which the camera uses sensors to detect the area of maximum focus and contrast.

TLR Twin-lens reflex camera:- this type of camera uses a secondary lens of focal length equal to that of the main lens. A fixed mirror reflects the image from the viewing lens up onto a ground- glass screen. These type of cameras suffer from parallax especially when focused at close range owing to the difference in position between the taking lens and the viewing lens.

Camera lens:- There are three types of lens each referring to the focal length of the lens measured in millimetres The three commonly used lens are:-

Normal:- (usually 45 to 55 mm produce an image which is about the same as what the human eye would see),

Wide-angle:- (lens with a focal length from 20 to35 mm provide a larger field of view and greater depth of field) and

Telephoto:- (Compact lens which gives a long focal length with a short back focus).

Focal length:- the distance between the rear point of the lens and the focal plane, when the focus is set at infinity.

Zoom lens:- 80- 200mm. Lens designed to allow a continuously variable focal length without altering the focus or f-numbers. When there is not enough natural light a photographer will use artificial light to illuminate a scene or subject. This can either be a strobe tungsten lamp or electronic flash. The once most popular light source of its time was the flashbulb for its intensity and disposability. This consisted of a bulb filled with a small mass of magnesium alloy and oxygen, which gave off a large burst of light. As we progressed through photographic development this was replaced by the electronic flash which consists of a glass quartz tube filled with an inert gas -a halogen (reactive element such as bromine). When a electric charge is applied to the two electrodes at each ends of the tube, the ionised gas within, produces an extreme burst of light for only a few seconds. The photographer can achieve maximum lighting if the light source is synchronised with the shutter of the camera. This is achieved by a connection between the two known as a hot shoe or a synch cord which connects the camera with a flash some distance away.

Automatic flash units:- The modern flash unit is linked to the camera by means of an electronic sensor which adjusts the duration of the flash for a particular setting, measuring the intensity of light. Flash units came in various sizes from camera mounted units to large scale studio units.

Exposure meters:- Instrument used to measure the amount of light on or being reflected by an object. This then allows the photographer to measure the aperture size and shutter speed. Exposure meters come in four different types:-

Flash:- (Artificial light which gives a brief burst of illumination),

Spot:- (artificial light using a lens, reflector and a strong beam of light with a controllable width),

Incident light:- (Measurement of the amount of light falling on to a subject. The meter is placed by the object pointing towards the light).

Reflected light:- (this type of light meter measures the amount of light reflected and bounced off the object. The light meter is pointed toward the object).

Studio photography:- Colour temperature meters work off a scale which expresses the content of a light source and the colour quality this is represented in Kelvin’s. Colour sensitivity is the response of sensitive material to colours of different wavelengths.

Filters:- Coloured glass or gelatine or plastic disks which modify the light colour balance passing through them. They are also used to change the intensity of the brightness, contrast and to create fog or a haze.

Light balancing filters:- are used to alter or make small adjustments in colour. To balance the greenish fluorescent light given off by day light a colour - compensating magenta filter is used. A polarizing filter is used to counter act the polarized light responsible for reflections and glare from non metallic surfaces such as glass, water, paint. There are various other filters in the market today available to photographers. These include colour compensating filters, light balancing filters, conversion filters.Click here to recap the fundamentals to digital editing techniques. Click here

Development:- the process of converting exposed silver halides to a visible negative image. When this negative is used to create a positive image, this is classified as a print. To achieve accurate development, the image needs to be placed in a developer (chemical bath which contains reducing agents which alter exposed silver halides to black metallic silver, forming large grains of silver around small particles to form the image, thus making it visible) at a suitable diluted temperature. The density and thickness of the silver deposits depends largely on the correct amount of light received during exposure. Chemicals such as accelerators:- (this speeds up the action of the reducing agent in the solution, these chemicals are usually alkaline), preservatives:- (usually sodium sulphite, this prevents oxidation of the reducing agent in use) and restrainers:- (this chemical prevents the reducing agent from altering the unexposed halides and converts them to black metallic silver). Fixation:- Chemical bath used to alter unused halides to a soluble silver complex in both negative and prints, making the image visible in white light. Two common ones which are used are ammonium thiosulfate and sodium thiosulfate. Hypo eliminator:- (commonly termed a clearing agent) this removes traces of the fixing agent from the emulsion.

There are two methods by which to print. This first being "Contact". This type of paper is coated with a silver chloride emulsion of a very slow speed and is used when making prints of the same size as the negative are required. The negative and the printing material are placed to together under a light source. The second being "Projection printing". A low powered vertical mounted slide projector within which a negative is placed and light passes through the lens. An enlarged image is superimposed onto light sensitive printing paper. By controlling the exposure "amount of light" falling on certain sections of the printing material. A photographer can darken and lighten certain area's.

Printing material:- This type of of paper is less sensitive than that of normal film. Once it has been exposed, the printed is developed and fixed. In the final result areas that where blocked from light by the negative come out as light tones, areas exposed to loads of light come out as dark tones. Colour prints derived either by the projection or the contact method and are classified according to their grade.

Colour negatives and positive colour transparencies are printed on multilayered responsive paper with colour sensitive forming agents. There are various examples of this such as the kodak Ektachrome type 34 process which are used for printing colour transparencies. The agfacolor CN type A, fujicolor and ektacolor are formed in a dye-forming solution having no reversal processing.

A separate negative is prepared for each colour in the dye -transfer process. This can either be produced from a colour transparency. Matrices:- which are derived from the negative to produce positive-relief images on gelatine sheets. The result is three positive matrices, one red, blue and green. Each is then printed onto an easel to get the precise alignment and registration to produce a perfect colour image in full.

In recent years the advancement of technology has revolutionised the way in which we visualise and produce photographic images. Modernity has seen the development of smaller and compact cameras with electronic procedures for recording an image. The Mavica still video camera developed by the Sony Corporation has the added advantage of recording images onto a floppy disk and being played back via an external monitor. Canon entered the market not long after with its RC-470 still-video camera, which records 50 still images on to a 5 cm floppy disk with 300 & 400 lines of resolution. This type of camera can be connected to the television to view images.

The manipulation and alteration of an image by means of its binary coding paved the on set of the digital computer age. This meant the photographer was no longer reliant on a second party to produce and resolve issues, which he could process himself.

In the late 1980's the Scitex image processing system and commercial and advertising industry standard, allowed the operator the ability to manipulate, erase, change colour tones, alter and adjust contrast and picture sharpness. Earlier computer technology, did not permit total picture quality when it came to image resolution, balance in tones and saturation. Specialised systems such as the Montage slide writer, Linotronic and presentation technology are used to produce glossy crystal clear magazine images.

In 1931, the American engineer Harold E. Edgerton designed an electronic strobe light that allowed him to photograph a moving bullet with a flash speed of 1/500,000. Objects in motion could now be photographed on the same film. A photocell synchronized to the strobe flash light allowed for a moving object to be caught on film.

The development of the high speed magneto optical and electro-optical shutters enabled exposure times of up to a few billionths of a second. Both using a concept of light polarisation that can cause light to rotate under a magnetic or electric field. The magneto-optical shutter is a glass cylinder which is placed in a coil with a polarisation filter placed at each end. Light passes through the first filter and becomes polarised and is stopped by the second filter. Once an electric charge is passed through the coil, the light in the polarisation plane will rotate and light travel through the cylinder. The electro-optical shutter:- of two electrodes and a cell that are filled with nitrobenzene and is situated between the two crossed polarisation filters. Inside the polarisation plane the liquid is rotated by an electrical pulse at each point of the electrodes. This type of optical shutter has been used to photography the occurrence and sequence of events of an atomic bomb.

Aerial photography:- special large format cameras (5 ins 12.7cm), used for mapping, reconnaissance, survey rural and urban planning . There are different types:- air to air, air to ground and air to sea. This type of photographs exposure is related to the speed of the aircraft and the ambient light conditions. An ultra-violet filter is used to stop haze (thin mist caused by small particles). These type of cameras have long focal lengths and a very high optical resolution for picture detail and clarity.

Underwater photography:- these type of cameras are built to within a water tight casing and built to with stand extreme pressures. By using a wide angle lens the photographer is able to eliminate the 25 percent refractive index caused by the magnification of the water.

Scientific photography:- the photographic emulsion of these types of film is very sensitive to gamma rays, ultraviolet and infrared light. Various equipment of different sizes and strengths are used to take photographs of subatomic particles and molecules and are used to document chemical reactions under a controlled environment. Photography can be used as a diagnostic (called an X-ray, radiography) tool in medicine.

Using gamma rays to x-ray metal strengths and to verify safety in components where pressure is exerted, as in airplanes and nuclear power stations. The development of the laser, enabled the photographer to have lens less photography which is three dimensional and is called a hologram.

Astronomical photography:- the placement of the photographic plates in the focal plane of a telescope gives the astronomer wider scope and clarity. The photographic plate has the ability to record by long time exposures. Image enhancing techniques as the starlight liberates electrons on to a photo cathode that is put into the focal plane of the telescope. The free electrons join and form an image on the plates. Computer technology sharpens and cleans up the quality of the finished result.

Microfilming:- This is film used to record a micro-scopic record of documents and is intended to be projected onto a monitor or screen at a later date. The benefit of microfilm is its compact size and the ability for lots of information to be stored in a small space.

Infrared photography:- Infra-red film which has colour sensitive emulsion which makes light. It is usually exposed using an infra-red transmitting filter over the front of the camera lens to prevent other wavelengths from the spectrum from penetrating. Organic foliage appears as white as they reflect infrared light. The film can also be used under a no light condition, using an infra-red emitting lamp or flashbulb, both being not visible to the eye. It is especially useful for the military in covert operations at night to detect the enemy. In addition to its qualities in detection, it is also used medically to diagnose certain skin disorders and other medical conditions.

Ultraviolet photography:- electromagnetic radiation having a wave length just shorter than a violet light but longer than an x-ray. A filter is used over the camera lens to absorb ultraviolet radiation. A UV filter enables a photographer to penetrate the haze, whilst having no effect on the exposure. Ultraviolet photography is used in the detection of forged documents. Plastic and chemicals replace the silver-halide emulsion of film. The surface area of the plastic exposed to ultraviolet light hardens relative to the amount of exposure. Once the unhardened area is removed a raised image is given. Chemicals when exposed to ultraviolet rays emit gas bubbles. These bubbles expand and become visible on the application of heat. This creates a transparency and the bubbles form an image.

Photography as an art form:- There three main reason and types of photography. This includes Reportage:- What you see is what you get. This is nonmanipulative and is used in the documentation and recording of events and news. This is usually objective in its approach as the photographer will select what is to be recorded and will plan ahead of time or calculate the risks at the precise time of taken an image. Roger Fenton 1853 - 1856. An English photographer, who first documented the war scenes during the Crimean war. Matthew Brady 1823 - 1896. An American who become famous for his photography of the American Civil war.

Photojournalism:- the use of images to convey a story in full. Photojournalists work for daily newspapers and magazine, news publications. The photojournalist is able to cover a diverse range of topics, some times multi tasking his role from day to day. French photojournalist and surrealist Henri Cartier-Bresson 1930 created documentary photography, what he would call the decisive moment. His work is considered fine art and documentation photography. He was one of the first photographers to travel and the photo essays he produced still stand up today. Pictures became commerce. Bresson pictures were highly atmospheric and captured the true sense and feel of life as it stood, poverty, humanity and nobility. Robert Capa:- Similiar is style to Bresson, Capa was interested in capturing the impact of battle scenes and war in great detail and the civilians it encompassed. His most famous images were of the U.S troops landing in Europe during the 2nd world war. Pictorial magazines such as Life and Look in the United states in the 1930's was established and they conveyed photographic essays to the general public. These magazines went onto provide coverage of Korean War and the World War II (1950 - 1953). Many photographs taken by photojournalists have a hidden meaning for social change and modernity "progression". As in the case of the two documentary photographers Ernest Cole who's work (1967) the "House of Bondage" explored the miseries and depravation of the South African Apartheid system. And Czech Josef Koudelka for his work and images on the plight of the eastern European Gypsies.

Art photography:- This is subjective and uses a manipulative:- (light, focus and photo alterations occur either in development or print) and nonmanipulative approach. Daguerre 1787 - 1851 Daguerreotype was the first photographic process in Paris. Daguerreotypes took the world by storm and he was most successful in the field of portraiture. A few years later the Daguerreotype was superseded by William Fox Talbots 1841 who patented it, thus becoming obsolete with the introduction of the Cooldion process:- (Wet plate photographic process introduced in 1851 by F. Scott Archer). Calotype:- (Photographic process using paper negatives.) Iodised paper requiring lengthy exposure was used in the camera. This consisted of using thin iron sheets instead of glass plates and this had the added advantage of producing a negative, from which multiple copies could be made, it consisted of using paper coated with silver iodide.

Commercial and Publicity Photography:- Since the 1920's photography has been used to influence consumerism and publicity for various commercial products and services. This was either used in advertisements, magazines and books and various other form of publications The quality and clarity of the image has improved and this has made it more viable as a means to convey a product or service. As the public gain an impression straight off what they see before physically touching or sampling the services.

Straight Photography:- Several California photographers in the 1930's formed a nonmanipulative photography group called the f/64 (this being the diaphragm aperture on a lens that gives the best depth of field). These photographers who were Cunningham, Weston and Adams, came to the believe that the photographer should capture in a scene details at a close range and at a distance in clear sharp focus. Cunningham and Weston went onto specialise in natural abstract forms whilst Adams predominantly photographed the lights effect on the Western united States sceneries.