Sequence viewing > Index - Alternative Photo Emulsions - Resource - © Lloyd Godman

Alternative Photographic Processes - (Hand made photographic -emulsions and processes)

Processes - Salted Paper Prints

This section on salt printing many thanks to Wynn White

Check out Wynn's work

A dash of salt
A description of the salted paper print process with some interesting variations.
Always be careful when handling chemicals. Read the health and safety instructions.

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.

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.

Image above: William Henry Fox Talbot

Photogenic drawing of a fern leaf, c.1835-40


Salted paper printing process
Recipe I:

Table Salt Sodium Chloride 2.0 gm
Distilled Water to make 100.0 ml
Silver Nitrate 12.0 gm
Distilled Water to make 100.0 ml


I recommend starting with this recipe since it is the most basic. The amount of salt can be altered slightly but at three grams per 100 ml the paper prints a very faint violet unless double coated with silver. At four grams per 100 ml I could only get a faint violet image. It is possible to make prints with much lower salt concentrations than the standard 2%. Substituting ammonium chloride for sodium chloride moves the print color from sepia towards more of a reddish brown and also increases print speed slightly. The amount of silver nitrate solution can be lowered to around 10% (10 grams per 100 ml).

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.


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.

Recipe II: Tokyo Bay Water


Tokyo Bay water: 50.0 ml
Distilled water to make 100.0 ml
Silver Nitrate 12.0 gm
Distilled water to make 100.0 ml


I collected the bay water in a Suntory whisky bottle that had washed up on the beach. When I got home I boiled it to kill the plankton. Coating and drying are the same as in Recipe I. The problem with using sea water is that it is difficult to judge how much salt there is in the water. One method of testing for salinity calls for silver nitrate, one of the main ingredients of the salt print.

I learned that there is, on average, 35 grams of salt in a liter of sea water and slightly less in bay water due to fresh water runoff. I mistakenly calculated that it was a 30~35% solution and mixed my first salting solution one part bay water to fifteen parts distilled water. Even with this small amount of salt I was able to get a nice print that was quite pink in color. After realizing my mistake I made another salting solution mixing it one to one and got a sepia colored print.

Image above: Rocksurf (Tokyo Bay Water print).

Note: If you absoulutely have to try this variation but don't have access to Tokoy bay water, Wynn will be happy to send you some, just send him the postage... ;-)

Recipe III: Wynn's Favorite
Sodium Chloride 2.0 gm
Potassium Citrate 2.0 gm
Distilled water to make 100.0 ml
Silver Nitrate 12.0 gm
Distilled water to make 50.0 gm
Citric Acid 6.0 gm
Distilled water to make 50.0 ml
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.

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.

Image above: Potassium Dichromate Bottles

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
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.

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

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.

Image above: Printing Frame in UV Printer

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. 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.

 

 

 



Salted Paper Prints 1834-1850s Discovery William Henry Fox Talbot invented the salt paper print process in 1834. This process was used: - to make prints first from Talbot's photogenic drawings - from the early 1840s onwards, to make prints from calotype negatives produced by Talbot and others. - later, occasionally to make prints from collodion negatives on glass Process Create the Image 1. Immerse fine writing paper in a weak solution of common salt (sodium chloride). 2. Blot the paper to dry it. 3. Coat the paper with a 20% solution of silver nitrate. This creates silver nitrate crystals. These are deposited within the fibres of the paper; not held in by gelatin as was the case with later processes. The amount of silver deposited in the paper was only about one tenth the level that is found in modern prints. 3. Lay the negative over the paper and expose to sunlight. Fix the Image 4. After exposure fix the image to ensure that it remains captured on the paper. Fixing can be achieved by using: - a concentrated solution of silver nitrate - hyposulphite of soda ('hypo') as is used today, or - one of the halides such as silver iodide. The use of sodium hyposulphite (hypo) to fix prints was known from the early days, but Talbot continued to use his concentrated silver nitrate (salt) solution. The early photographers in St Andrews also persisted with salt fixing their prints, and had difficulty achieving successful results. Later, Talbot changed to using silver bromide to fix his prints. A more popular fixer, used by others was silver iodide. Silver chloride and potassium bromide could also be used. Hill & Adamson experimented with several of these fixing solutions. 5. After fixing, wash he print thoroughly to remove the fixer and prevent it subsequently damaging the print. Some photographers washed their prints for 12 to 24 hours or longer, perhaps using 20 changes of water. Blanquet- Evrard's Announcement - 1851 The above is a 'printing-out process'. This is the process that was normally used. However, Louis-Desiré Blanquet-Evrard, in 1851 announced that it was possible to produce prints more quickly by developing, fixing and washing, as for a negative. Result Hill & Adamson's Results The results was a small brown image, which could be delightful when well printed, though many early photographers had difficulty making successful salt prints. SALTED PAPER PRINT from a CALOTYPE NEGATIVE © Sheriff Munro and his daughter by Hill & Adamson The success of the process, and the amount of detail retained in the calotype depended on many factors, including the batch of paper used. Talbot often used Watman's Rag Paper. Turner's Patent Tablotype paper gave excellent results in the late 1840s and early 1850s. Much of the paper produced today includes bleaches, or even hypo, and so is not suitable for making calotype prints. Fading The image was very delicate and liable to fade. Fading can be reduced by the exclusion of air. e.g. when two prints have been pressed together in a photographic album, they tend to show less fading. Many of Talbot's images have faded badly. Hill & Adamson's images have survived better, apart from fading around the edges of some. This may be due to the care taken by Adamson in making the prints - possibly even due to some particular aspect of Adamson's processing. DO Hill remarked that Adamson "... thinks he knows some things others do not." Tones in the Print Tones of salted paper prints can vary from reddish-brown to chestnut brown; purplish brown if toned with gold chloride for greater permanence; yellowish brown if faded. They sometimes exhibit a lilac tone. This is likely to occur in prints fixed with silver chloride, and is due to incomplete removal of silver by the fixer. They sometimes exhibit primrose yellow tones. This is likely to occur in iodide-fixed prints, and is due to silver chloride having been transformed to silver iodide. Surface of the Print Except for those that hae been glazed or varnished with a thin coating of albumen (so producing albumenized salt prints), salt paper prints have a matt surface. The tones are embedded in the fibres of the paper. Waxed Paper Negatives Waxing of the negative paper enabled more detail to be retained, and prevented the fibres of the calotype negative being seen in the final print. In Edinburgh Hill & Adamson The work of Talbot in Edinburgh, Hill and Adamson and other early Edinburgh photographers is mentioned on the page describing the Calotype process. SALTED PAPER PRINT from a CALOTYPE NEGATIVE © Sir David Brewster by Hill & Adamson Talbot left a documentary record of his methods for producing prints. Hill & Adamson did not.

http://www.edinphoto.org.uk/1/1_early_photography_-_processes.htm


 

Want to learn more? - do a workshop or one on one with Lloyd Godman