Реферат по предмету "Иностранный язык"


Photography Essay Research Paper When someone says

Photography Essay, Research Paper

When someone says the word photography the first thing that most

people think of is pictures. People never think of what goes in to the

developing process. They do not think about all the chemicals that go into

developing the pictures. Many people just wonder why their picture came back

with nothing on it or why they look like a ghost. They do not even bother to

think about all the chemistry that goes on to develop the pictures. They think of

how much money they just wasted on a bunch of messed up pictures. If they

were to sit down and think about all the chemicals that went into making that

one picture they would view it differently. Photography is just another form of

chemistry when it comes down to it.

In the year 1864 a chemist by the name of Joseph Wilson Swan

produces the first way to develop film. (Joseph). What was known as the auto

type process was created by using a gelatin film soaked in carbon or other

pigment granules. This process would then be photosensitized by using

potassium dichromate. Later in 1879, he produced the bromide printing paper

that we now use in standard photographic medium.

Since photography has been around for about 100 years the chemicals

used to make both motion pictures and still pictures are the same. (AWP) Both

motion and still photography share many similar chemicals such as fixers,

developers, and stop baths. Also from the very beginning the durability and

stability of pictures has been a problem. The fine-grained and superficial

silver, the paper and plastics as base, the gelatin, albumin as binding agents,

which was found in many black and white photos were affected greatly by the

environmental conditions.

It was not in till 1935 that Kodak came out with the first color film. That

was the birth of modern day film. The durability of the color film though was

worse then the black and white. With the color dyes and no longer the metallic

silvers the colors were under the problems of the environment. They had to be

put under sun light, chemical agents, heat, and moisture. Then when the

pictures where stored wrong the colors also got bleached out.

It is virtually impossible to restore the original photo. (AWP) So now

the goal of these people who are trying to restore these black and white photos

is to reproduce the original colors of the bleached photo instead of restoring the

original dyes. Not only do we face the problem of faded photographs we also

face the problem of having to fix scratched or dusty films. In order to remove

the scratches a classical liquid gate printing method gets used. The liquid gate

is applied to both sides of the original film. The liquid fills the scratch and

reduces the light scatter.

When processing film most photographers prefer to use black-and-white

film because of how much easier the development process is. When you

develop the photographs you need to have developers, stop baths, fixers,

washing aids, wetting agents ,water, film cleaner, reducers and intensifiers, and

paper. (Davis) Each of these agents have there own purpose to be used.

Many of the chemicals also come in liquid or powder form.

There are two kinds of developers; one for film use and one for paper.

(Davis) The most common developing agents are hydroquinone, Metol, and

phenidone. (Photographic) Some other developers that are not as common are

Amildol, Benzotriazole, Borax, Chlorquinol, Glycin, Hydroquinone, and

Kodalk. Developing agents are to weak to work alone so they must work with

an accelerator.

The accelerator is used to activates the developing agent. When you mix

a developer with a strong accelerator you will get a quicker developing time and

a higher contrast. The quicker accelerator also has bad side effects like

excessive fog, soft emulsions, course grain, and shorter developer life. The

most typical accelerators are; sodium hydroxide, sodium carbonate, Kodalk,

borax, and sodium sulfite. When using the developer and accelerator you also

want to use a restrainer. The restrainer is added to reduce the chemical fog, the

chemical fog is caused by an unexposed silver halide crystals . The restrainer

also is used to slow the developing action in areas that receive less exposure.

Most restrainers are potassium bromide and benzotriazole.

After the developers the next step would be to dip the picture into a stop

bath. (Davis) The most common stop bath is made of 28% acetic acid, which is

usually diluted before use. The stop bath is used to stop the action of the

developers and it also helps to prolong the life of the fixers. Another stop bath

that can be purchased is a stronger form called Glacial Acetic Acid. This acid

is extremely toxic and is not recommended for use. Many stop baths contain

certain chemicals that change colors to tell you when that stop bath is becoming

exhausted. (Photographic) Many people will substitute water for the stop bath

but by doing this they are not stopping the action of the developer. That is a

common mistake mad by many people.

The fixer, also called the hypo, is used once the developer has developed

the image. (Davis) Some fixers that are commonly used are Boric acid,

Formaldehyde and sodium sulfite. (Photographic) The fixer is used to

stabilize the image, but it to must be washed away. (Davis) If you leave the

fixer on for to long it will eventually cause staining or fading of the image.

(Photographic) If used correctly the fixer is to dissolve the undeveloped silver

halide crystals from the film or paper. If you are using poor paper they will

stain due to the darkening of the silver halide crystals.

Most fixer contain a fixing agent, it is the most active part of the fixer

in removing any undeveloped silver halide crystals. It also contains acid such

as acetic acid. This stops the developing action usually when no stop bath is

used. A preservative is also included, it is used to prevent disintegration of the

fixer by the acid. The fixer also includes a hardener and buffer. The hardener

is usually used in film development to keep it from softening and scratching.

When it is used on prints it causes spotting and toning. The buffer, usually

boric acid, is used to keep the acidity of the fixer if a hardener is used.

The washing aids and wetting agents are now brought into play after

you have used your fixer. The washing agent is used after your fixer instead

of having to wash it for 30 minutes to remove al fixer residue, you get to

quickly treat it in a washing aid for five to ten minutes. (Davis). The wetting

agent is used on and only for film. Once your film has been washed you want

to give it a quick treatment in your wetting agent to ensure that it dries evenly.

Once you have your picture developed you can use a toner. The toner

changes the tone of your finished prints. (Davis) The toner is used to darken

your black and white photo to a shade darker or more. (Photographic) You

can also use the toner to tone out the spots in a image. The most common

toner used is Potassium Ferricyanide.

When photographers go to set up there dark room they usually set up a

wet and dry side. (Davis) They usually do this so when working with the wet

side, the chemicals, they will not risk getting their already developed pictures

ruined. Just by touching a developed picture while you have a little bit of a

chemical on your fingers can ruin it. When working in your dark room you

want to be sure that you have no light leaking into your room, the leaking of

light into the room can cause the film to get exposed before you are ready to

treat it with the chemicals.

Silver halide is a term used to explain to combination of silver and a

halogen element. (Photographic) A few halogen elements are bromine, chlorine

or iodine. The silver halide crystals respond to the light that is reflected off of

the image. The silver is affected more by the lighter areas because of how

they reflect light unlike the dark areas which absorb the light. Many silver

halide crystals have very distinctive six-sided shapes. When developing the

photographs these crystals either get developed or they get washed off of the

picture during either the stop bath or after they developed photo has been fixed.

An alternative development of film would be emulsion. (Photographic)

Emulsion is a gel that is stored at room temperature, in order to use it you must

heat it to 110* in order to liquefy it. When you go and pour the emulsion in to

a container to use you want it to also be heated other wise the emulsion will

solidify. Once you have your emulsion poured so you can use it you want to

spread it evenly on to your papers, you want it to spread out evenly. Once

the emulsion is spread evenly you want it to dry, you need to put the piece of

paper that you have coated with emulsion into a safe dark place where no

dust particles will get embedded on it.

After you have dryed your paper you can begin to print you picture on it.

(Photographic) To develop your emulsion you go through the same steps you

used for your black and white photos. Be sure that you use a hardening fixer,

preferably in powder form. You would then need to rinse the photo for ten

minutes at the least to remove all the excess chemicals. When working with

emulsion you want to use hand coated papers and fresh chemicals.

When handling photographic chemicals you want to be wearing goggles,

an apron, gloves, and an organic vapor respirator. (Photography) When

working in your dark room you also want to have and air change at least ten

times an hour. They also recommend that you have exhaust ventilation for

processing and mixing tanks.

When working with these chemicals they tell you that you should never

add water to acid you should always add acid to water instead. (photography)

You should also avoid and products that contain benzene. Doctors have found

that benzene if inhaled can cause cancer.

When storing your chemicals you want to make sure that they are out

of the reach of small children and pets. (Photography) When storing acid you

want it to be placed in a nonmetal unbreakable container. All other chemicals

should also be placed in non-breakable containers and then placed inside of

another plastic container. All of your diluted solutions should be marked

clearly with the date you mixed it and whet chemical it is. This helps so you

will not use any outdated chemicals.

When it comes to disposal you want to make sure that all unmixed

chemicals are disposed of through a licensed hazardous waste handler.

(Photography) If you are unable to get a licensed waste handler you can go

through a professional household hazardous waste collection. It is better if

you are able to use up all of your chemicals. When you no longer need your

left over chemicals before throwing them away you should check with local

schools, professional photographers, or ever photographic materials suppliers to

find out if they want your unused chemicals. After checking with local agencies

and finding that they don t need your left over chemicals then you should go

about throwing them away the proper way.

Hopefully now when people hear the word photography they will not

think of only the bad pictures they get back from Wal-Greens or K-Mart, but

they will think of all the time and effort that people put into developing those

pictures for them. People should think of photography as something fun to do

in their free time but they also need to remember all to the chemistry that goes

in to developing their photos. They also need to realize all of the chemistry that

went into making the roll of film that they are using in their fancy cameras.

Every one should know bout the developers , the stop bath , the fixers , the

washing aids , the wetting agents , and all of the toners that are used to develop

that one single roll of film they used. But when using chemicals people must

also remember that you must use safety and protection. When handling

photographic chemicals you must have all skin covered, you must wear goggles,

you need to wear a breathing mask and you must also wear gloves. When you

are using chemicals you also want to be sure that you dispose of them the

proper way. You should never flush or pour chemicals down the sink or toilet.

So not only is photography something to do in your free time but its chemistry,

as you develop pictures you are learning chemistry.




Не сдавайте скачаную работу преподавателю!
Данный реферат Вы можете использовать для подготовки курсовых проектов.

Поделись с друзьями, за репост + 100 мильонов к студенческой карме :

Пишем реферат самостоятельно:
! Как писать рефераты
Практические рекомендации по написанию студенческих рефератов.
! План реферата Краткий список разделов, отражающий структура и порядок работы над будующим рефератом.
! Введение реферата Вводная часть работы, в которой отражается цель и обозначается список задач.
! Заключение реферата В заключении подводятся итоги, описывается была ли достигнута поставленная цель, каковы результаты.
! Оформление рефератов Методические рекомендации по грамотному оформлению работы по ГОСТ.

Читайте также:
Виды рефератов Какими бывают рефераты по своему назначению и структуре.

Сейчас смотрят :

Реферат Особенности употребления артикля в современном английском языке
Реферат Исследования коэффициента деятельностного развития студентов 3-4 курсов физико-математической специальности
Реферат Общие принципы построения систем отображения навигационной информации используемые в электронной
Реферат Атмический план 34 миры во вселенной 35 восприятие поля 36
Реферат Оптимизация преподавания теоретических дисциплин в новых условиях обучения (на примере курса «Основы теории второго иностранного языка»)
Реферат Агролесомелиоративное картографирование и моделирование деградационных процессов на основе аэрокосмического мониторинга и геоинформационных технологий
Реферат The Canterbury Tales Analysis Essay Research Paper
Реферат «доверительный кредит»
Реферат Ядерная физика и строение Солнца
Реферат Судьба поколения 1830-х годов в лирике М.Ю.Лермонтова
Реферат Keith Haring Essay Research Paper Keith Haring
Реферат Влияние циклических спадов на рынке ценных бумаг на инвестиции
Реферат The Mysterious Bermuda Triangle Essay Research Paper
Реферат Capital Punihment Essay Research Paper CAPITAL PUNISHMENTby
Реферат Конкурентная борьба