Salt Print with descriptions of orotone, opalotype, varnishes… – Historical & Alternative Photography
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Preface

This book, Salt Print, is the third in a series of books about the old photographic techniques and modern approaches to these techniques. In this book, the reader will discover step-by-step the entire manufacturing process of photographs which are made with the help of silver nitrate and salted water, beginning from the production of photographic sensitizers, continuing with development, toning, fixing, and right up to the final step of varnishing the photos.

First, we will learn three basic techniques of salt printing. But, since a small confusion comes in the description of these techniques, I decided to further enlarge the confusion with a somewhat more understandable description. This I found in a fairly well known book from 1866, The Silver Sunbeam, by J. Towler. Towler separates positive printing from the salted binder which is applied to the paper. Thus, he mentions plain paper, albumenized paper, and arrowroot paper. In this book, we have, of course, replaced his concept of »positive printing« with »salt printing« because all of the above-mentioned procedures are, in fact, salt printing. The concept of plain paper I have renamed with today’s better-known definition: salted paper.

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In our definition, salt printing is, therefore, the technique of printing with silver nitrate onto various surfaces (e.g., paper and glass) which are, in turn, coated with various salted binders.

In this book, I will, of course, as in all of my books, somewhat supplement the knowledge that is found in other books. We will start to learn two basic processes of developing photographs. For all three of the above-mentioned forms of salt printing, the old masters in the early years of photography most commonly used the so-called print-out technique, which was then called printing by sun. In this technique, the image appears gradually until its final stage. The second basic process, which today’s historical or alternative photographers are almost not familiar with at all, but which the old masters were using since around 1850, is the so-called developed-out technique, which was then called printing by development. In this technique, the photo is only partially exposed for a few minutes and then developed with a simple proto-developer. In this book, we will learn about one of the oldest processes of developing with gallic acid. I added, as well, a description of development of salted prints with modern developers. This book describes the process of developing with Agfa’s Rodinal developer.

In the third part of the book, I describe a fast method for making digital negatives, with all of the peculiarities with which the reader should be familiar, in order to produce his first digital negative. More about digital negatives, which is quite an extensive topic, is, of course, found in the book Easy Digital Negatives, which is part of this series and available through all Amazon bookstores.

Following the descriptions of salt printing and digital negatives, the reader will learn about toning, both archival toning (which increases the stability of photos) and color toning (which is intended to modify the final color of photo). The main focus is, of course, given to the gold toners, which were the most popular.

Then follow descriptions of advanced techniques, which we can hardly find in other modern books on salted print. First, we will learn a very easy printing technique on colored salted paper, which was extremely popular before the beginning of the 20th century. This technique is followed by a brief description of how to manually paint photos, in our case with modern acrylic paints.

But the old masters didn’t print only on paper. They also used glass. In this book, we will learn about a very popular procedure of opalotype, or printing on a white, milky glass. But the highlight of this book is certainly a description of one of the most beautiful photographic techniques, which, according to my information, is currently mastered by only three or four people. I’m talking, of course, about orotone, or printing on glass that is coated with gold or a similar glittering background.

The whole process of salt printing is completed in this book with some rarely described processes of coating and varnishing used for beautifying and protecting photos.

Peter Mrhar

The history of salt printing

The history of photos which are made with the help of silver nitrate and salted water, or so-called silver chloride, is still somewhat shrouded in the mists of various specific interests, so we will mention only a few basic milestones.

1724 German scientist Johann Heinrich Schulze (1687 – 1744) discovered that the silver compounds are sensitive to light. He made the first photograms, whereby he wrote a text on a sheet of paper (the first negative in the world) coated with light-sensitive solution. Unfortunately, he was not able to preserve or fix the resulting images.

1777 The Swedish chemist Carl Wilhelm Scheele (1742 – 1786) continued the experiments with silver solutions and discovered that ammonia washed away unexposed silver chloride, while exposed metallic silver was left unchanged. The resulting picture was then fixed for the first time.

1816 The first photographer, Joseph Nicéphore Niépce (1765 – 1833), made his first photograph (negative) using a camera obscura and silver chloride. Because he didn’t know how to fix the image, he began to experiment with bitumen. The first silver photo he produced was preserved until around 1860, but has since disappeared.

1823 Joseph Nicéphore Niépce produced the first photo in the world using bitumen. This image is preserved to the present day.

1833 The French-Brazilian scientist, Antoine Hercule Romuald Florence (1804 – 1879), took the first photo with the help of a camera obscura and silver chloride; it was made on the principle of a negative and a positive image. He named his own process a photographie. Photos were fixed with solution made from urine. His photos are not preserved; however, what has been preserved until the present day are a few of his photograms – photocopies of documents and labels, made with the help of negatives.

1839 French photographer Hippolyte Bayard (1801 – 1887) wanted to patent his own photographic process, today so-called direct positive printing, a sort of Polaroid of the 19th century, but he failed. Academics give priority to the French photographer Louis-Jacques-Mandé Daguerre (1787 – 1851). Bayard first darkened a paper coated with salt water and silver nitrate in the sun then he smeared potassium iodide all over it and exposed it with the camera. The photographs were fixed with ammonia.

1839 French photographer Louis-Jacques-Mandé Daguerre (1787 – 1851) patented the »first« successful photographic process – daguerreotype.

1839 A few days later, William Henry Fox Talbot (1800 – 1877) showed his negatives and photograms made with silver chloride at the Royal Institution of Great Britain in London.

1839 On 24 of June 1839, French photographer Hippolyte Bayard displayed photos made by his process. This was the first photographic exhibition in the world.

1839 English scientist John Frederick William Herschel (1792 – 1871) discovered that sodium thiosulfate (hypo) is a much better fixer than ammonia. He informed both Daguerre and Talbot about this discovery.

1840 French physicist Armand Hippolyte Louis Fizeau (1819 – 1896) discovered that toning with gold solutions amplifies the daguerreotype image.

1841 W. H. F. Talbot patented the photographic process using negatives. Photos were developed with the help of gallic acid.

1842 Slovenian photographer Janez Puhar (1814 – 1864) invented the first usable photo on glass, which was made by the daguerreotype process. During the period when the patent for the invention was being considered, although it was made public and known, authorities delayed granting the patent until 1851.

1847 Claude Félix Abel Niépce de Saint-Victor (1805 – 1870), a cousin of Joseph Nicéphore Niépce, made the first albumenized negative on glass, which significantly exceeded the quality of Talbot’s paper negatives.

1849 Photographers Jean-Baptiste Gustave Le Gray (1820 – 1884) and Frederick Scott Archer (1813 – 1857) discovered the importance of collodion for photographic negatives on glass.

1850 French photographer Louis Désiré Blanquart-Evrard (1802 – 1872) upgraded printing on plain salted paper. He coated paper with egg white and salt, which creates a much sharper image on the surface of the paper. This technique of printing on albumenized paper became the main photographic printing technique from 1855 until the beginning of the 20th century. In that same year, Blanquart-Evrard discovered a process for developing positive images with the help of developers. This process allowed photos to be exposed and developed within a few minutes, regardless of the weather.

1854 Louis Alphonse de Brébisson (1798 – 1888) began to use salted paper with a starch binder. Photographers quickly discovered that the most suitable is starch made from the tropical plant known as arrowroot (lat. Maranta arundinacea).

1895 Arthur von Hübl (1853 – 1932) published the formula for matte-albumen paper, which soon became one of the most popular papers for salt printing.

1920 Salted papers were replaced with more modern, silver-gelatin papers.

A brief description of the process

In this section, to quickly gain a better understanding of the content which is described in the following chapters, a brief, schematic description of the general salt printing procedure is presented. More information is presented in the description of each process.

Preparation of negatives

To print positive images in the case of the salt printing, we need a properly corrected negative. This can be made in several ways, with the help of paper negatives, film, or glass plates, and, these days, with the help of so-called digital negatives. In this book, we will focus only on the use of digital negatives.

  • see About digital negatives
  • see Standard printing time
  • see Printing a digital negatives

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Preparation of materials

Before we start to work, we have to collect up all the materials and tools that we will use. These, of course, depend on the way in which we want to make the photograph. We mustn’t forget appropriate personal protection. In the case of salted print, we always have to wear latex gloves.

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Applying binder

The first step is application of the binder onto the paper or glass. It can be applied in daylight by various methods. On salted, arrowroot, and matte paper, the binder is most often applied with a brush; however, on albumenized paper, the binder is almost always applied with the so-called floating paper technique. In that case, the paper is most commonly left in the fluid for five minutes.

  • see Brushes
  • see Floating the paper

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Drying paper

After applying the binder onto the paper, it is hung on a string and dried for 5 minutes. However, arrowroot, albumen, and matte paper are dried for 30 minutes or one hour.

Drying in all these techniques is finished with a hair dryer.

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Sensitizing with silver nitrate

After drying, the entire photographic process is carried out in a darkened room. In doing so, we can use a red light or, more often, a tungsten lamp with power of 40 W or less.

Silver nitrate can be applied in several ways. On salted and arrowroot paper, a glass rod or a different kind of brush is used, but on albumenized and matte paper, the silver nitrate solution is almost always applied by a 3-minute soak in a so-called silver bath.

  • see Glass rod
  • see Floating the paper

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Drying the sensitizer

After application of silver nitrate, the paper is dried in the air in a dark place for about five minutes. It is then dried with a hair dryer.

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Exposing salted prints

Completely dry paper, which has now become sensitive to UV light, is exposed with the sun or, more frequently, with the help of UV lamps. Photos are exposed using a contact frame.

  • see Standard printing time
  • see Contact frames

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Rinsing and developing

When using a print-out technique, we have to move the exposed photo from a printing frame to slightly salty and acidic distilled water. Then we gently agitate the tray for three minutes. The technique for developed-out photos is the same as the process just described; the only difference is that now we have to put the photo in the selected developer for an appropriate time.

After initial rinsing in water or development in the developer, the photo is washed for three minutes in plain water, so that it is thoroughly washed.

  • see Water for rinsing
  • see Developers

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Toning

Since the making of photos with the help of silver nitrate is quite unstable compared to other photographic techniques (for example platinotype, carbon print, gum printing, etc…), the »silver« photos are almost always toned with various toners. Most of these toners are used before fixing the photos, as toning prevents fading in the fixer; but some toner or other, in our case selenium, is almost always used after fixation. After toning, the photo is washed in plain water because in order to remove all unwanted compounds from the photo.

  • see Toners and toning

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Fixing

Photos are fixed in a 10% solution of sodium thiosulfate. We may fix the photo in one or two trays of fixative, usually for a total time of 5 to 10 minutes. I personally fix photos in one tray for a period of 5 minutes.

  •  see Making a photographic fixer

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Clearing fixer

After fixing the photo we need to thoroughly wash away all remnants of fixer, as this can ruin a photo. There are again more cleaning techniques, but nowadays the photographic fixer is most commonly neutralized using a solution of sodium sulfite. The cleaning process takes from 2 to 3 minutes.

  • see Neutralizing the fixer

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Final wash

After fixing the photograph, it must be thoroughly rinsed under running water. The final rinsing takes 15 minutes in the case of using the above-mentioned clearing agent; however, a photo must be washed for at least 30 minutes in the case where the clearing agent is not used.

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Final drying

A photo can be dried in many ways. Among amateur photographers, the most popular drying technique is between two heavy glass plates and paper towel. When the paper towel becomes moist, we must replace it with a dry one.

Toning after fixing

As we mentioned, we can tone photos before fixing photos. However, in the case of selenium toner or toning with color toners such as iron blue toner, the toning is performed after fixing and the final wash. In this case of toning, we immerse the photo for an appropriate time in the selected toner. After toning, the photo is washed for 30 minutes in running water for the second time.

  • see Iron blue toner
  • see Local and double toning

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Varnishing and coating

The last step in the production of photographs is protection against external influences. At the same time, this also significantly improves the appearance of photos. For this operation, we can use various varnishes or wax coatings.

  • see Varnishes and waxes

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Salted print binders

The binders which are used in salt printing are of various types, but the bases of all such solutions are ammonium or sodium salts, i.e. Ammonium Chloride or Sodium Chloride, commonly known as table salt. The surface of paper coated with the binder, in conjunction with silver nitrate, forms the light-sensitive compound of silver chloride.

Differences in color of photographs, though mentioned in various sources, and which should be the result of the above-described salts, are almost non-existent, so that the reader can choose any salt which is readily available.

In addition to these chemicals, we will also use some other compounds in our formulas. Potassium citrate, which is found in most of the old formulas, is meant to increase the density of the image; citric acid should extend the emulsion stability on paper, etc…

The old photographic masters usually added additional gelatin binder to the formulas. This improves the adhesion of the chemicals on paper, and also slightly increases the brilliance of the photos.

When we add a purified egg white into the salted water, we get a binder for albumenized paper. When we add starch into the salted water, we get a binder for so-called arrowroot paper. Instead of arrowroot starch, we may, of course, use any starch, for example, starch made from corn, potato and the like. However, arrowroot starch is considered to be the best, due to its tiny structure.

Sodium chloride is common table salt, but for salted prints we commonly use refined salt, which can be purchased in pharmacies or chemicals stores. In the table salt, quite a lot of chemical additives are found, and these could destroy the image.

Potassium citrate can be made at home. In a glass of water we dissolve some citric acid. Then, to that solution, we begin to add pinch after pinch of sodium carbonate. When the solution, despite the addition of more sodium carbonate, stops bubbling, we get saturated potassium citrate. Then a glass of this solution is left for a few days on a window shelf, so that all the water evaporates. The dust that remains in the glass is potassium citrate.

Warning. Prior to each production and use of chemical solutions, it is best to read the instructions and warnings. Information on safety, the so-called MSDS (Material Safety Data Sheet), can be found online or in relevant manuals.

 

Salted paper

In this chapter, we will learn about some tested formulas that were used by the first photographic masters for the production of salted paper photographs. As we mentioned earlier, modifying the formulas will not create any noticeable differences on the photograph, so that the presented formulas can be used almost identically to the originals.

The classic formula

To produce this formula, with which the first masters prepared salted papers, we need the following:

  • 30 g sodium chloride (NaCl) or ammonium chloride (NH4Cl)
  • 10 g citric acid (C6H6O7)
  • 1 l distilled water
  1. Preparation of the solution is very simple. With a precise scale, we weight out 30 grams of purified table salt (sodium chloride). Purified salt can be purchased at any pharmacy, and instead of sodium chloride we may, of course, use ammonium salt.
  2. The measured salt is poured in 1000 ml of distilled water and completely dissolved.
  3. Then we weigh out 10 grams of citric acid with the precision scale. (Citric acid can be purchased in any supermarket.) We then mix it in the dissolved salt solution.

The classic formula with gelatin

To create this formula, in which gelatin is added, and which achieves a higher gloss on the photo, we need the following:

  • 2 g gelatin
  • 30 g sodium chloride or ammonium chloride
  • 10 g citric acid
  • 1 l distilled water
Warning. Unlike sodium chloride, ammonium chloride is harmful. It causes irritation to the eyes and is harmful if swallowed or inhaled.

 

Making a gelatin solution

The gelatin used in this technique is a simple kitchen gelatin. We will need a 0.2% solution of gelatin, which is made according to the manufacturer’s instructions or according to the following procedure:

  1. From the specified 1 liter of distilled water, we pour approximately 100 ml into a small bowl. Then we slowly add 2 g of gelatin.
  2. We wait 15 minutes for the gelatin to thicken.
  3. Then we place the bowl of gelatin into a pot of water heated to about 45°C.
  4. When the gelatin liquefies, we stir it slowly for a few minutes.
  5. Bubbles generated during mixing can be removed with the edge of a paper towel.

The classic formula with gelatin

  1. Now we can produce the remaining part of the formula. With the precision scale, we weigh out 30 grams of salt. As we have already mentioned, it is best to use purified table salt without any additives. Instead of common salt, we can use ammonium salt.
  2. The salt is then added to the remaining 900 ml of water and stirred until completely dissolved.
  3. Then we weigh out 10 grams of citric acid using the precision scale; this is added to the dissolved liquid with salt that we just made in the previous two steps.
  4. In the end, the warm gelatin is poured in 900 ml of the prepared solution and stirred slowly, to avoid the formation of bubbles.
  5. The liquid is carefully poured into a bottle and labeled with the appropriate information.

The formula with potassium citrate

The formula described here is one of the classic formulas, to which is added the potassium citrate; this should increase the density of the image. The solution is made using the following chemicals:

  • 20 g sodium chloride (NaCl)
  • 20 g potassium citrate (C6H5K3O7)
  • 1 l distilled water

The photo on the next page was printed on Arches Platine paper, which generates almost black tones. The binder was made from the above-described classical formulas. The photo was not toned nor varnished.

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Method for producing the solution

  1. With a precision scale, 20 g of sodium chloride is weighed out.
  2. The salt is added into 1000 ml of water and stirred until completely dissolved.
  3. Then, 20 grams of potassium citrate is measured out with the precision scale and stirred in the dissolved salt solution described in steps 1 and 2 above.
  4. A bottle is used to store the solution and is marked with an appropriate label.

Copyright © 2016 Peter Mrhar.