Historical - Daguerreotype vs. Calotype

 



Daguerreotype framed in glass



Louis Jacques Mande Daguerre invented daguerreotype photography in France in the 1830s. Henry Fox Talbot created the Calotype several years later. Daguerre discovered that he could expose an image onto a copper plate coated with iodized silver. He found that the image lasted if it was exposed to mercury vapor and a salt solution. Daguerreotypes were put on polished silver, so they were reflective. The daguerreotype is a negative image. It was framed so it wouldn't tarnish.







Calotype of the Colosseum



Talbot came up with a bit of a different photographic process. He first brushed photographic paper with a salt solution and let it dry. Next he brushed it with silver nitrate and let that dry, creating a silver chloride. Then Talbot added Gallic acid to make the paper more sensitive to light. After being exposed he would fix the image with an iodized solution. Finally, to develop the photo, a negative was placed on top of photo paper, laid flat in a glass frame and exposed to sunlight. Unlike the daguerreotype, the Calotype negative allowed for an unlimited number of prints.

JBird

Please insert a caption under the photos

This is a 50 mm lens. The diaphragm is set at the maximum aperture (F1.8). Use this type of diaphragm when you have low light. The higher aperture allows more light into the camera, allowing more exposure to the image. With a larger aperture, allow for a smaller depth of field.

This is a 50 mm normal lens. The diaphragm is set at the minimum aperture. Use this type of diaphragm when there is a lot of light present and you need to create a larger depth of field. The minimum aperture is never the best. The best aperture is 2 stops from the smallest aperture and 2 stops from the largest aperture (5.6-11). 

This camera is set at a 400 iso. This controls the internal light meter. Set film at the same iso for proper light exposure within the camera.

This is an external light meter. Set the iso according to the external light meter and the film you have in the camera. 

On the lower right, you can count the number of shots still available on your roll of film. On the upper right, you have the lever to load your film. On the left, you can set your shutter speed. The "B" setting allows for extremely high exposure. 

This is how you load your film- It is important to set the top of the film in the rocket. Pull three times before taking the first pictures.

Take care to insert film properly.

When you finish the roll you must rewind the roll. When you insert the roll, always check that this rocket turns.

Push the silver button to turn the film in the rocket.

WARNING!!!!

If your camera is an olympus om10
the switch should be put on AUTO, not on B
This is why the strong overexposure!!

Week 4: Developer and Fixer Effects on Film (KD)

Developer: 

When a photo is taken and the shutter opens, light hits the film and it becomes exposed. When the film is exposed, an invisible image is formed on the film called a latent image. The developer is what makes this latent image visible. It makes the parts of the film that have been exposed by the light darker creating what we recognize as a negative. The developer transforms the light sensitive chemicals in the film, silver halides, that record the image to elemental silver. The longer the developer is in contact with the film, the more silver halides are changed to elemental silver, therefore, the darker the image. The ideal time the film is washed in the developer depends on the type of film and can be found on the bottle of developer being used.

Fixer:

After the film has been processed with the photographic developer and washed with water, it is treated with photographic fixer. The fixer is a crucial step when developing film because the fixer stabilized the image on the film and keeps it from being further affected by light. It does this by removing the silver halides that have not been exposed leaving behind only the elemental silver that had been changed by the developer and created the visible image. The active ingredients in fixers are various sulfates.

Katherine

Week 4: Daguerreotype vs. Calotype (KD)

Daguerreotype:

The Daguerreotype method was invented in 1830's. It uses copper plates coated in an iodized silver and requires a rather long exposure of twenty or more minutes and then fixed with salt solutions. Mercury was first used to develop the latent image on the plates. Daguerre was the first to develop and publish this process. The Daguerreotype method is very similar to the method we use in film photography today. Using a developer to change and remove the silver halides and then a fixer to keep the film from being further affected by light exposure.

Calotype:

The Calotype method was introduced in the very early 1840's. It does not use copper plates as the Daguerreotype  method does. Instead of silver halides as the light sensitive element, silver iodide is used and that exposure to light is what changes the silver iodide to silver rather than the use of a developer after exposure. The pure silver is the oxidized, which turns it black, producing the image. Then potassium bromide is used to stabilize the image rather than salts.

Katherine

Week 4: First Film Photo (KD)

I like birds. Pigeons aren't my favorite, but they are all that are around here. So I guess I have to like pigeons.

Katherine

Chemicals Effect on the Negative

Photographic processing through use of chemicals transforms the latent image into a visible image, making a permanent image insensitive to light. In this process, film is soaked in water in order to swell the gelatin layer. The image is then converted to metallic silver. A stop bath, a solution of acetic acid or citric acid, is used next, or water can often be used if the developer wishes. The fixer makes the image forever permanent and light-resistant by dissolving silver halide salts.

Coco

William Henry Talbot

In 1839, Talbot devised an improved process to form a negative picture on transparent paper coated with silver salts. Such an image still required an exposure of at least a minute, but many positives could be made from a single negative image by exposing a second light-sensitive sheet through the negative image itself. Talbot called these images calotypes, from the Greek for"beautiful." This method of converting a negative to a positive is the basisfor modern photography, and for this reason Talbot is considered to be one of the two founders of photography. The announcement of Daguerre's process in France moved Talbot to present his"photogenic drawing" to the Royal Society in 1839. By the autumn of 1840, Talbot had discovered that gallic acid sped up the development of latent images,and in 1841 he patented his perfected process, now calling it the Talbotype. He developed a way to speed up the exposure of images by coating the photographic paper repeatedly with alternate washes of salt and silver, then exposing the paper in a moist state. This vastly reduced the exposure time required for portraits, and the agonizing effort required to remain still during a sitting was eliminated.

Cricket

Film Structure

The positive imagine To create a negative image on  the film, different levels of light determines black areas, white areas, and grey tones. The film is divided into different parts.  The Base of the film forms the structure of the film. The size of the film is from 4/1000 to 7/1000 of an inch thick. One side of the film is shiny white the other is opaque, this is helpful for handling during both manufacturing and the developing process. The photochemical side is made up of up to 20 different layers that all turn out to a total thickness of about 1/1000 of an inch. Between the layers there is gelatin to keep the layers in place. When the negative is not exposed the layer is transparent. The 20 layers are responsible for the chemical reactions that filter the light; they don't all help form the picture. 


-Zee

William Henry Fox Talbot - Klimka

William Henry Fox Talbot

William Henry Fox Talbot was a British inventor and photographer who lived in the 19^th century. He was the inventor of calotype process, the precursor to most photographic processes of the 19th and 20th centuries. Talbot engaged in photographic experiments beginning in early 1834, before Louis Daguerre exhibited his pictures taken by the sun. In February 1841, Talbot obtained a patent for the calotype process. At first, he was selling individual patent licences for £20 each, but later he lowered the fee and waived the payment for those who wished to use the process only as amateurs. Professional photographers, however, had to pay up to £300 annually. Talbot's behavior was widely criticized. One reason Talbot patented the calotype was that he had spent many thousands of pounds on the development of the calotype process over several years. It is also significant that, although the daguerreotype process was supposed to be free to the world, Daguerre secured a British patent on his own process making it illegal for people in Britain to practice his process without a license. 

Klimka

Daguerreotype Process (by HCM)

Louis Daguerre was a professional scene painter for the opera, who was interested in the effects of lighting. He began experimenting with the effects of light upon the translucent paintings in the 1820s. During this time he used a camera obscura to aid painting with perspective, which sparked his interest in finding a way to keep the image still. In 1829, Daguerre began a partnership with Joseph Niepce in order to improve upon the photography process which Niepce had invented, where the photographs quickly faded. After several years of experimentation, Daguerre developed a more convenient and effective method, which is now known as the daguerreotype. Some believed his discovery was a mistake; In 1835, he put an exposed plate in his chemical cupboard, and a few days later he found that the latent image had developed. Daguerre concluded the development of the photograph was caused by the presence of mercury vapor from the broken thermometer, which later led to the discovery that future images could be developed with a shorter exposure time.

PROCESS: 

The daguerreotype was the first commercially successful photographic process, where a highly detailed  image is a direct positive made in the camera on a silver plated copper plate. This sliver-plated copper plate had first to be cleaned and polished until the surface looked like a mirror. Next, the plate was sensitized in a closed box over iodine until it took on a yellow-rose color. The plate, which was held in a lightproof holder, was transferred to the camera. Once the sensitized plate was placed in the camera, the lens cap would be removed in order to being the exposure. After exposure to light, the plate was developed over hot mercury until the image appeared. To fix the image, the plate was immersed in sodium thiosulfate or salt and toned with gold chloride. 

The exposure times for the first daguerreotypes ranged from 3 to 15 minutes, making the process impractical for portraits. Later modification to the sensitization process and improved photographic lenses helped reduce the exposure time to less than a minute. Daguerreotypes could also copied thought a process known as "redaguerreotyping". 

PLATE SIZES: 

• Whole plate 6-1/2" x 8-1/2"
• Half plate 4-1/4" x 5-1/2"
• Quarter plate 3-1/4" x 4-1/4"
• Sixth plate 2-3/4" x 3-1/4"
• Ninth plate 2" x 2-1/2"
• Sixteenth plate 1-3/8" x 1-5/8"

CAMERAS:

The earliest cameras were made by opticians and instrument makers, and sometimes by the photographers themselves. Most cameras utilized a sliding-box design, with the lens placed in the front box. The second, slightly smaller box slid into the back of the larger box. Focus was controlled by sliding the rear box forwards or backwards. A laterally reverse image would be obtained (unless the camera had a mirror or prism to reverse the image on the plates). 

-HCM-

Week 3

William Henry Fox Talbot

      Henry Fox Talbot was born on February 11, 1800 was a British inventor and pioneer of photography. In fact, he invented what is called the "calotype" process of developing pictures. This method includes using paper coated with silver iodide, and was the precursor to most photographic processes of the 19th and 20th centuries. Besides this, Mr. Fox Talbot was a noted photographer and was very involved in introducing photography as an artistic medium. His work in the 1840's on photo-mechanical reproduction led to the creation of the photoglyphic engraving process the precursor to photogravure. Talbot is also remembered as the holder of a patent, which is said to have greatly affected the early commercial photography of Britain. Throughout his life, Talbot took many well known pictures of Oxford, York and Paris, he is remembered and gratified for his overall involvement in the development of photography.

-erinn

Film Structure

Black & White

Photographic film will only react when it is exposed to light. Different levels of light determine the black areas and the gray tones to create a negative image on the film. The base of the film is made up of a transparent celluloid material which is about 5/1000 of an inch thick. One side is shiny and the other side is opaque. On the photochemical side of the film up to 20 different layers are added. Each layer is held in place by gelatin. These layers not only help form images, but also control chemical reactions and filter light. The silver halide crystals are light sensitive, basically they react to different levels of light to create an image. Depending on where you are taking pictures determines the exposure speed of the film. If you are outside in bright light you may want 100. Indoor photos may call for 400 or so.

Color

Color film is a bit more complex. The first layer contains blue-sensitive silver halide and a yellow forming color coupler. This reacts with the developing agent to generate dye in all of the areas where a silver image is produced. Then there is a yellow filter. The second layer contains blue and green sensitive silver halide as well as a magenta-forming color coupler. The next layer is blue-and-red sensitive and has cyan forming color coupler. There is then an antihalation layer, a safety film base, and a backing layer.

JBird

Film Structure

Photos form from light reflecting off the surface that is being photographed. Film is made up of various layers which all have a different purpose: the gelatin layer protects from scratches, the emulsion layer which takes up the light, substrate layer which adds adhesion to the emulsion, and a film base. Roll film can be added in the daylight without exposing all the film but once it is in the camera, cannot be exposed to light or else the film would be ruined. This film is coated with a light-tight backing layer.

-Cam