by Gerald Boerner

  

JerryPhoto_8x8_P1010031 From early in the history of photography, the alternatives for producing finished photos was either a clear, but non-reproducible Daguerreotype or a print from a paper Calotype negative. In the latter case, the typical reproduction process was using a Salt Print. Henry Fox Talbot, the developer of the Calotype, focused most of his attention on reproducing his photos through a mechanical photogravure process.

The Salt Print was created by coating a plain paper (like that used for watercolors) onto which a sizing layer was applied followed by a silver salt solution. The negative was placed over the sensitized paper and exposed to bright UV light, generally from the sun. The exposed print was then washed in water, toned with a gold or platinum solution, washed again, fixed in hypo, and the thoroughly washed again.

These prints were then mounted for the client. The problem with these Salt Prints comes about when any one of the washing steps is not completed successfully; leaving silver salts in the print could continue to develop in sunlight, destroying the image.

This was an example of the “Printing-Out” process, as discussed in a previous post. The Salt Print was replaced in the mid-1850s by paper coated with collodion which was processed by a “Developing-Out” process that was less likely to be damaged by time if properly processed.  GLB

    

“Not everybody trusts paintings but people believe photographs.”
— Ansel Adams

“Life is not significant details, illuminated by a flash, fixed forever. Photographs are.”
— Susan Sontag

“In my photographs it is apparent that there was no posing at the moment I released the shutter.”
— Jerzy Kosinski

“In the photographs themselves there’s a definite contrast between the figures and the location – I like that kind of California backyard look; clapboard houses, staircases outdoors.”
— Helmut Newton

“If you meet people who have been successful in Hollywood, or look a their photographs, you see a haunted look in their eyes, you sense a trapped feeling.”
— Meg Tilly

“If we limit our vision to the real world, we will forever be fighting on the minus side of things, working only too make our photographs equal to what we see out there, but no better.”
— Galen Rowell

“I’ve looked at photographs of myself during concerts and it sometimes looks as if I’m in a fencing move, with a guitar in my hands instead of a sword.”
— Neil Diamond

“I’m not photographing the model in the classic sense; the model is playing a part in my photographs. It’s more like theater. I always work with models I know, and I let them participate in deciding how to act their part.”
— Kim Weston

  

Note:
This posting is intended for the educational use of photographers and photography students and complies with the “educational fair use” provisions of copyright law. For readers who might wish to reuse some of these images should check out their compliance with copyright limitations that might apply to that use.

GLB

  

Early Photographic Technique: The Salt Print

The salt print was the most paper-based photographic process before the advent of the albumen print. It was in use during the period from 1839 through approximately 1860.

The salted paper print was the first type of paper print used in photography, and remained the most popular paper print until the introduction of the albumen in the 1850’s. The salted paper technique was created by British photographer William Henry Fox Talbot. He called his process calotype printing, but today the method is more commonly known as salt prints or salted paper prints.

Salt prints could be made from both paper and glass negatives. Paper negatives produced a grainy and slightly mottled image. Glass negatives produced a sharp, crisp image. Salt prints have white highlights.

William Henry Fox Talbot

William Henry Fox Talbot was a British inventor, born on February 11, 1800 and died on September 17, 1877. He was the inventor of calotype process, the precursor to most photographic processes of the 19th and 20th centuries. He was also a noted photographer who made major contributions to the development of photography as an artistic medium. His work in the 1840s 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, some say, affected the early development of commercial photography in Britain. Additionally, he made some important early photographs of Oxford, Paris, and York.

Talbot was known by his second name Henry, rather than William. It is commonly assumed that "Fox Talbot" is an unhyphenated double-barrelled surname. However, Fox came from his mother’s maiden name and was not passed on to his children. Some historians have therefore argued that he should be referred to as ‘Talbot’ rather than ‘Fox Talbot’. Nevertheless, although he signed his name as H.F. Talbot as well as H. Fox Talbot, he was most often referred to by his contemporaries as ‘Mr Fox Talbot’ or ‘Mr H Fox Talbot’, including by his mother. ‘H Fox Talbot’ was also the style he chose for his most important publications, including The Pencil of Nature.

Making a Salt Print (Modern Method)

Combine hydrochloric acid and sodium hydroxide and what do you get? That’s right, sodium chloride commonly known as table salt. Salt is one of two key ingredients in the making of salted paper prints.

Henry Fox Talbot Image by William Henry Fox Talbot

The salted paper process was invented by William Henry Fox Talbot, known as The Father of Modern Photography, in 1833 while he was on his honey moon. He was the first to make a silver image on paper. On his first attempts paper coated with a silver nitrate solution and exposed to light only gave a faint metallic silver image. He later discovered that by first applying salt to the paper and then coating it with the silver nitrate solution he could get a much stronger image. This is basically the same way that we make salt prints today.

Salted Paper Printing Process

Method

Step 1: Mix up the salting solution. Before coating write the name of the paper on the back in pencil for future reference and also so that after it is coated and dried you will be able to tell which side the coating is on. Smooth, preferably hot press, paper works best. It is important that the paper not be too porous since the solutions will have a tendency to sink in too deeply. One paper that I have found to work nicely with no additional sizing is Rising Stonehenge. Using masking tape, tape the paper at the corners to a heavy sheet of glass. Measure out an appropriate amount of salting solution. I use a pipette that I have marked so that the amount of solution won’t vary from print to print. Coat the paper. I like to use a glass rod for coating.

A detailed description of glass rod coating can be found at Bostick & Sullivan. http://www.bostick-sullivan.com/newbook/Page_thumbs.htm.

Use a foam brush or hake (Japanese generic term for brush) if you want prints with painterly brush marks. Allow the paper to dry. A hair drier at any setting can be used to speed up the process. Salting can be carried out under bright light and the salted paper will keep indefinitely.

coating Coating the paper

Step 2: After the salted paper is dry, under safelight conditions, coat it with the silver nitrate solution. Salted paper is mainly sensitive to ultraviolet light so exposure to low level tungsten light will not fog it. Just to make sure that my paper doesn’t get fogged I work under the light of a 7 watt, yellow light bulb placed one meter above my coating area and another one above my darkroom sink. Be very careful not to get silver nitrate on your skin or, more importantly, in your eyes. It could blind you. If you use brushes you should use a separate brush for each of the two solutions. I use two separate pipettes and coating rods.

Step 3: Dry the paper in the dark. If you use a hair dryer use the cool setting. The paper is now ready for printing and should be used right away to avoid fogging.

Wynn White’s Favorite Recipe

Salting Solution

  • Sodium Chloride 2.0 gm
  • Potassium Citrate 2.0 gm
  • Distilled Water to make 100 ml

Mix the salting solution and coat the paper. I use a coating rod.

Silver Solution

  • Silver Nitrate 12.0 gm
  • Distilled Water to make 50.0 ml

Citric Acid Solution

  • Citric Acid 6.0 gm
  • Distilled water to make 50.0 ml

Just before coating combine equal parts of the silver solution and citric acid solution. Coat the dry, salted paper with the silver nitrate/citric acid solution. If the citric acid is added to the silver solution and then stored, after time, an unwanted precipitate will form. The citric acid helps prevent fog.

Sodium chloride is used in this recipe but ammonium chloride gives results that are almost the same. The amount of potassium citrate can be lowered or omitted and sodium citrate can also be used in its place. Citrates seem to give deeper richer browns.

I mask off my prints to give a neat border around the image area. With the basic salt recipe I kept getting slight to moderate fog in the masked area. After adding citric acid to the silver nitrate solution the fog went away. I strongly advise masking, at least in the beginning, so that you can see whether or not your prints are clearing properly.

Contrast Control

The safest and most natural way to gain contrast if you are using a UV printer is to use sunlight. The boost in contrast is substantial.

A very efficient but more dangerous method of contrast control utilizes potassium dichromate. Before using this chemical you should be familiar with its hazards. An MSDS for potassium dichromate can be found at jtbaker.com/msds/englishhtml/P5719.htm.

A general rule would be never to let it come in contact with any part of your body or to breath in any potassium dichromate dust, even in minute quantities.

dichromate Potassium Dichromate Bottles

I have mixed solutions of potassium dichromate from .5% to 10% and keep them in separately numbered bottles; each bottle being successively .5% more concentrated. Before coating I add one drop of an appropriate potassium dichromate solution to the measured out salting solution. With greater concentrations of dichromate exposure times become increasingly longer. I generally work in the .5% to 2% range.

Sizing

In a good salted paper print the image is sharp, rendering great detail. If the coating solutions soak too deeply into the paper the image will be in the paper rather than on the surface thus causing the image to appear dull and lack detail.

Depending on the paper, I apply a 1-3% (1-3 grams per 100 ml) gelatin sizing. To prepare the sizing add the gelatin to 25 ml or so of distilled water at room temperature. Unflavored gelatin purchased at the grocery store works fine. Let the gelatin bloom for about 20 minutes and then add the final volume of water at 40-50 degrees C. Stir the solution gently with a glass stirring rod. It is now ready to be used.

I pour the solution into a clean print tray and then immerse the paper in the solution. I lift the paper from the gelatin solution and let most of the liquid run off of it back into the tray. I then place the paper, face down, on a piece of thick plexiglass that is resting at an angle and squeegee it with a glass coating rod that is larger than the paper. I turn the paper over and squeegee the surface. I hang the paper to dry on a line that is stretched above my darkroom sink.

As the solution cools it becomes very messy and difficult to work with. I regularly pour mine from the tray back into a pirex cup that sits on a coffee warmer. The optimal temperature for the solution is around 40-45 degrees C and it should not be heated to above 54 degrees C. If there is any sizing solution left over it can be covered and kept in the refrigerator for a few days to be used later after reheating.

Printing

Negative

Salted paper is categorized as printing-out paper and must be printed by contact. Due to the self masking nature of P.O.P. a negative with great contrast is needed for optimal results. Salt prints can render delicate shadow and highlight detail, perhaps better than any other printing process. If you have been exposing and developing your film for conventional silver-gelatin paper you probably don’t have a negative with adequate contrast for a standard salted paper print.

I make enlarged negatives using the Liam Lawless technique of reverse processing of lith film. It is economical and not so difficult to learn. A detailed description of this process is found in the article Less is More by Ed Buffaloe at Unblinking Eye.

Printing Frame

photo frame The Printing Frame

You will need a split back printing frame so that you can monitor your exposures without losing registration between the negative and paper. I use one that I purchased through Bostick & Sullivan and I am very happy with it.

mask The Photo Mask

For masking I use red construction paper that is just slightly smaller than the paper that I am printing on. I cut a rectangular opening just larger than the negative and place it on the paper. I place the negative inside the rectangle.

Light Source

printer Printing Frame in UV Printer

The sun is the most readily available light source and gives the best contrast. Drawbacks of using sunlight include variable intensity and long exposure times. It is quite easy to build a UV printer using black lights as the light source. Exposures are fast and intensity is constant. It is also nice to be able to print at night.

Exposure

Salt prints need to be exposed well past the point of looking just right because they will become much lighter during the processing sequence. After a little experience you will know when they are right.

Processing

Rinse

After you have determined that the print has received enough exposure take it out of the printer and rinse the unexposed silver. Most of what I have read calls for a simple rinse in running water but my tap water is quite alkaline at about pH 8 and has given me trouble with fog. To be on the safe side I rinse my prints in five consecutive trays of 1% citric acid solution for one minute in each tray. I fill four trays and after I have moved the print to the second tray I dump the first one, rinse it, and refill it. It now becomes tray number five.

Fixer

After the initial rinse salt prints must be thoroughly fixed. Be sure to use fresh fixer. I use a 10% solution of sodium thiosulfate (hypo) adding 2 grams of sodium bicarbonate to each liter of fixer. The sodium bicarbonate helps to hold back the bleaching that takes place and to keep the fixer slightly alkaline. I use two trays and fix for three minutes in each tray. After fixing prints should be immersed in a clearing agent such as Kodak Hypo Clear. I leave my salt prints in clearing agent for three minutes.

Wash

I wash my prints in an archival print washer for one hour and then hang them on a line above my sink to dry.

Salt Print Reducer (Bleach)

  • Potassium Ferricyanide .25 gm (one coffee stirrer spoonful)
  • Potassium Bromide  .2 gm (2 ml 10% solution)
  • Hypo 5.0 gm (10 ml 50% solution)
  • Water to make  1000.0 ml

Immerse the print in water and then check to make sure that there are no bubbles on the surface. It is then transferred to the reducer and agitated until the desired degree of bleaching is achieved. After reduction prints are treated in a clearing agent and then washed.

Salt Print Toner Recipes

Toning not only changes the image color of the salted paper print but also makes it much more permanent. The following toners can all be used before fixing or after. They all keep well and can be replenished.

Platinum Toner

  • Water 400.0 ml
  • Potassium Chloroplatinite (20% sol.) 1.0 ml
  • Citric Acid 2.5 gm
  • Sodium Chloride 2.5 gm
  • Water to make 500.0 ml

Place the print in the toner and agitate it until the desired tone is acquired; usually three to ten minutes. If you tone before fixing the print should be rinsed for at least a minute in running water before it goes into the fixing bath. This toner gives a warm gray tone.

Palladium Toner

  • Water 400.0 ml
  • Sodium Chloropalladite (15% sol.) 2.0 ml
  • Citric Acid 2.5 gm
  • Sodium Chloride 2.5 gm
  • Water to make 500.0 ml

Place the print in the toner and agitate it until the desired tone is acquired; usually three to ten minutes. If you tone before fixing the print should be rinsed for at least a minute in running water before it goes into the fixing bath. This toner gives a warm tone. Palladium toner has a tendency to lower contrast and also to move the color of the paper base from white to cream.

Gold/Borax Toner

  • Warm Water (38 degrees C) 400.0 ml
  • Borax 3.0 gm
  • Gold Chloride (1% sol.) 6.0 ml
  • Water to make 500.0 ml

After mixing the toner wait for one hour before using it. Place the print in the toner and agitate it until the desired tone is acquired; usually three to ten minutes. The print can go directly into the fixing bath if you tone before fixing. This toner gives a slightly warm tone.

Gold/Thiocarbamide Toner (my favorite):

  • Gold Chloride (1% sol.)  12.0 ml
  • Thiourea (1% sol.) 12.0 ml
  • Tartaric Acid (10% sol.) 12.0 ml
  • Sodium Chloride  5.0 gm
  • Distilled Water to make  250.0 ml

Add the thiourea solution to the 12.5 ml of gold chloride solution until the precipitate that forms is dissolved. The quantity of the thiourea solution should be slightly more than that of the gold chloride. Add the tartaric acid to 150 ml of distilled water. Add the gold thiourea solution to the acid solution and mix thoroughly. Last, add the salt and top the solution off with water to 250 ml and stir until it is uniform.

The solution requires no aging; it is ready for use directly after mixing. It tones highlights and shadows at the same rate so the print tones evenly and can be removed from the toning bath at any time. It keeps well and resists decomposition even after moderate use. Tones from plum red to neutral gray can be achieved with this toner.

In conclusion

Everything that I have written here has been tried and proven by me personally. I feel that I have only just begun my exploration of the possibilities of the salted paper process. Salt printing is quite flexible and offers the practitioner a multitude of creative avenues. None of the formulas in this report must be followed exactly and I urge you to experiment and to explore so that you can experience some of the joys and disappointments that our predecessors must have experienced back in the 19th century.

     

References

Background and biographical information is from Wikipedia articles on:

Wikipedia: Salt Print… 
http://en.wikipedia.org/wiki/Salt_print

Wikipedia: William Fox Talbot… 
http://en.wikipedia.org/wiki/William_Henry_Fox_Talbot

Web Sites and Blogs:

Alternative Photography: Dash of Salt…
http://www.alternativephotography.com/process_saltprints.html

Brainy Quote: Photograph Quotes…
http://www.brainyquote.com/quotes/keywords/photographs_3.html