تويت
التصوير الفوتوغرافي الحديث
التعرف على تاريخ التصوير ..
عملية الصفيحة الرطبة ..
عملية الصفيحة الجافة ..
WET PLATE PROCESS
In 1848 , a tremendous forward stride in the art of photography was made by the invention of the collodion or " wet plate " process for making negatives in the camera . R. J. Bingham , an outstanding English scientist and Gustave Le Gray , a noted French worker , suggested the use of collodion for photography , but Frederick Scott Archer was the first one to introduce a practical working process .
Archer made the first collodion negative in 1849. In 1851 , he published the details of this process . Up to this time , paper had been used as a base for negatives , but in the collodion process the base for negatives was glass .
The " wet plate " ( collodion ) process became very popular and soon displaced both the daguerreotype and talbotype processes . It was used almost exclusively between 1855 and 1881. The chief advantages of the process were extremely fine grain and clear whites . The chemicals used in developing and fixing the image were easily washed out of the sensitive emulsion and the negative or positive could be dried by heat . Wet plates were rather slow and they had the added disadvantage of having to be prepared just before taking the picture , since they had to be exposed while they were still wet . When a photographer wanted to take pictures by the wet - plate process , he had to carry quite a number of chemicals and a portable darkroom in which to sensitize and develop the plates .
Archer also introduced pyrogallic acid ( pyro ) as a developer for wet plates . He also designed a camera in which plates could be exposed , developed , and fixed . In spite of these important inventions which practically revolutionized the art of photography at the time , Archer lived and died a poor man .
DRY PLATE PROCESS
A very important invention , that of gelatino - bromide plates , the dry plates of the present which gelatin instead of collodion was used to carry the light sensitive silver salts , is credited to Richard Leach Maddox , an Englishman who became well known for his work in photomicrography . The result of his experiments with gelatin instead of collodion was given to the world in 1871 .
The photographic emulsions used today are essentially the same as those introduced by Dr. Maddox except , of course , they are vastly improved as to speed , quality and color response .
Since the invention of dry plates , great improvements have been made in materials and methods . The photographer of today has a wide choice of materials of excellent quality and is furnished with time and labor saving devices at every turn .
Possibly the most helpful improvement of recent years in making pictures is the introduction of roll film . This , more than anything else , has made hand - camera photography universal for commercial as well as amateur use . Roll films in their present form were invented by The Reverend Hannibal Goodwin and were placed on the market in 1889 by the Eastman Kodak Company .
In about 1903 , roll films were greatly improved and were made " non curling " by the simple process of coating the back with a thin layer of gelatin to counteract the pull of the gelatin coating on the front side .
Sheet films have now almost entirely taken the place of glass plates . They are generally coated on a base of cellulose nitrate or cellulose acetate very similar to roll films , but thicker .
التعرف على تاريخ التصوير ..
عملية الصفيحة الرطبة ..
عملية الصفيحة الجافة ..
WET PLATE PROCESS
In 1848 , a tremendous forward stride in the art of photography was made by the invention of the collodion or " wet plate " process for making negatives in the camera . R. J. Bingham , an outstanding English scientist and Gustave Le Gray , a noted French worker , suggested the use of collodion for photography , but Frederick Scott Archer was the first one to introduce a practical working process .
Archer made the first collodion negative in 1849. In 1851 , he published the details of this process . Up to this time , paper had been used as a base for negatives , but in the collodion process the base for negatives was glass .
The " wet plate " ( collodion ) process became very popular and soon displaced both the daguerreotype and talbotype processes . It was used almost exclusively between 1855 and 1881. The chief advantages of the process were extremely fine grain and clear whites . The chemicals used in developing and fixing the image were easily washed out of the sensitive emulsion and the negative or positive could be dried by heat . Wet plates were rather slow and they had the added disadvantage of having to be prepared just before taking the picture , since they had to be exposed while they were still wet . When a photographer wanted to take pictures by the wet - plate process , he had to carry quite a number of chemicals and a portable darkroom in which to sensitize and develop the plates .
Archer also introduced pyrogallic acid ( pyro ) as a developer for wet plates . He also designed a camera in which plates could be exposed , developed , and fixed . In spite of these important inventions which practically revolutionized the art of photography at the time , Archer lived and died a poor man .
DRY PLATE PROCESS
A very important invention , that of gelatino - bromide plates , the dry plates of the present which gelatin instead of collodion was used to carry the light sensitive silver salts , is credited to Richard Leach Maddox , an Englishman who became well known for his work in photomicrography . The result of his experiments with gelatin instead of collodion was given to the world in 1871 .
The photographic emulsions used today are essentially the same as those introduced by Dr. Maddox except , of course , they are vastly improved as to speed , quality and color response .
Since the invention of dry plates , great improvements have been made in materials and methods . The photographer of today has a wide choice of materials of excellent quality and is furnished with time and labor saving devices at every turn .
Possibly the most helpful improvement of recent years in making pictures is the introduction of roll film . This , more than anything else , has made hand - camera photography universal for commercial as well as amateur use . Roll films in their present form were invented by The Reverend Hannibal Goodwin and were placed on the market in 1889 by the Eastman Kodak Company .
In about 1903 , roll films were greatly improved and were made " non curling " by the simple process of coating the back with a thin layer of gelatin to counteract the pull of the gelatin coating on the front side .
Sheet films have now almost entirely taken the place of glass plates . They are generally coated on a base of cellulose nitrate or cellulose acetate very similar to roll films , but thicker .
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