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There is really nothing magic about the date 1885, except that around this time photography began to evolve into the state we know it today. Prior to this time, the Albumen Photograph ruled as the foremost photographic technique, but waiting in the wings, largely due to advances in making dry plate gelatin negatives, was the forerunner of the modern photo with 3 layerd paper, a new method of positive image production and improved tone/photo life...things were changing.....
First, a brief defination of a few terms is in order so you will be able to make sense out of what will follow in this and other posts.
Photographs on paper basically come about through one of two methods, (1) Printing out and (2) Developing out. The difference between the two is as follows:
Photographs made by the printing out process required the sensitized paper to be held in close proximity or in contact with the negative in a special frames and were then exposed to a bright light source, as in sun light, until the photographer judged that the tones were correct, at which time the photo was taken out of the frame , toned with gold and later a combination of gold and platinum, fixed and washed. The problem here was that the silver which composed the image was what is called photolytic silver, which refers to its physical form. The form was that of small, descreet globules which were very susceptable to further chemical reactions through the mechanisms of sulfiding and oxidative/reductive reactions. In short, even though toning helped to stabilize the photolytic silver, it still was unstable and tended to react with impurities at a rapid rate causing image deterioration. All printing out papers had this problem in some degree.
On the other hand, Developing out papers, in which the sensitized paper, usually a 3 layer type consisting of a base, a neutral(chemically) layer of Barium sulfate( called Barayta or Baryta) and the layer containing the silver, usually gelatin or collodian, were turned into photographs by briefly exposing the paper to light and the latent image was then developed in a seperate step using chemical "developing" agent(s), then fixed and washed. The major advantage here is what happens to the silver...in contact with the developer, the silver changes to a form known as Filimentary silver, charactarized by the silver forming clumps and twisted strands which better resist deterioration and gave more neutral tones.
O.K.... brief review....1885- Approx. the time when 3 layer papers, developing out processes for positive prints, and the use of gelatin and collodian as "binder layer" material to hold the silver began to be found in general use.
Two basic processes in use...Printing out and developing out. Of the two, Developing out had major advantages such as the ability to make Enlargments from a negative and the prints produced had better longivity and a more neutral tone.
The developing out process was, once mastered, clearly superior to the printing out process for general phtotgraphy and saw increasing use in studio type work.
Printing out processes didnt just go away...there are photographers today who still use it, but for specalized works. By 1920, developing was the prefered method of photo production...
and the commercial production of printing out papers ceased.
Next installment will deal with the two substances used as "binders" for the reactive silver...Gelatin and Collodian. Tom
First, a brief defination of a few terms is in order so you will be able to make sense out of what will follow in this and other posts.
Photographs on paper basically come about through one of two methods, (1) Printing out and (2) Developing out. The difference between the two is as follows:
Photographs made by the printing out process required the sensitized paper to be held in close proximity or in contact with the negative in a special frames and were then exposed to a bright light source, as in sun light, until the photographer judged that the tones were correct, at which time the photo was taken out of the frame , toned with gold and later a combination of gold and platinum, fixed and washed. The problem here was that the silver which composed the image was what is called photolytic silver, which refers to its physical form. The form was that of small, descreet globules which were very susceptable to further chemical reactions through the mechanisms of sulfiding and oxidative/reductive reactions. In short, even though toning helped to stabilize the photolytic silver, it still was unstable and tended to react with impurities at a rapid rate causing image deterioration. All printing out papers had this problem in some degree.
On the other hand, Developing out papers, in which the sensitized paper, usually a 3 layer type consisting of a base, a neutral(chemically) layer of Barium sulfate( called Barayta or Baryta) and the layer containing the silver, usually gelatin or collodian, were turned into photographs by briefly exposing the paper to light and the latent image was then developed in a seperate step using chemical "developing" agent(s), then fixed and washed. The major advantage here is what happens to the silver...in contact with the developer, the silver changes to a form known as Filimentary silver, charactarized by the silver forming clumps and twisted strands which better resist deterioration and gave more neutral tones.
O.K.... brief review....1885- Approx. the time when 3 layer papers, developing out processes for positive prints, and the use of gelatin and collodian as "binder layer" material to hold the silver began to be found in general use.
Two basic processes in use...Printing out and developing out. Of the two, Developing out had major advantages such as the ability to make Enlargments from a negative and the prints produced had better longivity and a more neutral tone.
The developing out process was, once mastered, clearly superior to the printing out process for general phtotgraphy and saw increasing use in studio type work.
Printing out processes didnt just go away...there are photographers today who still use it, but for specalized works. By 1920, developing was the prefered method of photo production...
and the commercial production of printing out papers ceased.
Next installment will deal with the two substances used as "binders" for the reactive silver...Gelatin and Collodian. Tom
It's got me baffled. Oh, hell, everything baffles me so what else is new. 
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