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ARGYROTYPE

HISTORIC OVERVIEW

Most photo historians agree that the brown print process originated of Sir John Herschel, who is credited as being the first to form an image with an iron sensitizer. He coated ferric ammonium citrate on paper, exposed it to light under objects, and developed the image by applying certain chemicals that reacted with the exposed iron paper.

Herschel discovered that a variety of solutions could develop the image. The developers included potassium ferricyanide, gold chloride, and silver nitrate. The prints he originated where called blue prints or cyanotypes; gold prints or chrysotypes; and silver prints or argentotypes. Herschel performed experiments with these salts repeatedly and reported their capacity to create images from the action of light in "Philosophical Transactions". Nevertheless, the processes remained little more then laboratory curiosities for about fifty years.

Throughout the middle of the ninteenth century, various researchers experimented with the processes herschel discovered. As a result, the knowledge that a silver image could be formed on paper sensitized with ferric ammonium citrate gradually filtered through the scientific and photographic community.

By 1850, iron silver printing was an idea whose time had come, and published discussions of experiments with iron printing processes proliferated. Most experiments led to no practical conclusion, until Willis perfected the Platinotype Process during the 1870s. Iron-Platinum printing paper reached a high state of comercial acceptance, becoming the paper preferred by the best photographers as a result of the efforts of the Willis Co.

During the early 1870s, the idea of printing with an iron sensitizer developed in silver became even more widespread as a result of the success of platinum printing. Printing with iron and silver, instead of iron and platinum was a conclusion to any passable student of chemistry. In 1890, W. W. Nicol patented a workable Kallitype process.

Since 1890, workers and writers have consistently viewed the Brown Print as a version of the Kallitype. For many years, the process of making Brown Prints has been widely taught as an old process or an alternative photographic process in many colleges and workshop photographic programs.

In the 1880s a variety of firms sold Brown Print products particularly to produce engineering drawings and as a general copy-all process, sold in the form of a light sensitive solution that individuals could coat on paper to make announcements, menus, postcards, and the like. The process was eventually used by amateurs as a paper that could be individually prepared for artistic use. Interest in brown print paper was sustained through the 1920s, by this time the process was well known in Europe and the United States. Articles dealing with the Brown Print, Sepia Print, Vandyke Process and water developed Kallitype can be found in numerous periodicals published in those countries.

The following is an example of a Brown Print sensitiser formula by E. Valenta in 1899:

Solution - A

Ferric ammonium citrate (green) 100g

Distilled water to make 1 ltr

Solution - B

Silver nitrate 140g

Diatilled water to make 600 - 800ml

Add a few drops of pure ammonia to solution B untill the precipitate first formed is re-dissolved. If an excess of ammonia has been added (this can be recognized by its smell), a very dilute sulfuric or citric acid solution should be added drop by drop untill the solution is rendered odorless.

To use mix 1 part solution A with 1 part solution B. Afew drops of 5% Potassium Dichromate can be added to increase contrast.

The Argyrotype Process was developed by Dr. Mike Ware in 1991. It is a reengeneered formula of theBrown Print, being more user friendly and resulting in better gradated and longer lasting images. As a one solution sensitizer is adds to darkroom conveniance, and the solution has a longer shelf life.

EXPOSING ARGYROTYPES

Coat and dry the art paper as discribed in " General Information - Coating".

Argyrotypes are printed by contact under the sunlight or other UV light source (see "General Information - Exposure"), and exposure is judged visualy, therefore a contact printing frame is very useful. The contact frame allows to inspect your exposure without moving the paper and negative from register. Two pieces of glass can be used with success, providing the paper and negative are taped in register to allow for inspection. The only draw back is that you will see the marks of the tape in the end.

Mike Ware's formula is faster then the traditional ones. The exposure time, obviously will depend on the intensity of the ultra violet radiation. As a rule of thumb, the exposure is carried out until the high lights show detail, and the midtones and shadows are nearly as dark as the tone desired in the final print. With little experience you'll be able to judge when a print is exposed enough.

PROCESSING

An exposed Argyrotype is developed by washing in a tray of gentle running water or in several trays of still water until the yellow stain from the sensitizer is completely removed. During this procedure a milky cloud will float from the paper. This is the result of the tap water washing away the unexposed sensitizer.

Contrast control can be achieved by adding a few drops of a 10% solution of ammonium dichromate to a water bath when developing the print (start with 10 drops per 500ml of water, adding more if necessary).

During washing, the print has a bright sepia colour. After washing, transfer the print to a weak Hypo solution, (Sodium Thiosulfate) for 3 min at 20 degrees C with gentle agitation. This is prepared by dissolving a levelled table spoon of Hypo in a liter of water at room temperature. This bath will treat aproximately ten 8x10 prints and should be discharged after each session. The print will gain a rich brown tone in the fixer.

Finally wash the print with gentle running water at about 20 degrees C for about 15 mn.

During all stages of wet processing, handle the print gently. Unlike modern photographic papers, which are supercoated (a layer of protective gelatine over the emultion), Argyrotype prints have their image laying on the surface of the paper without protection.

SEE "GENERAL INFORMATION HEALTH AND SAFETY"