by Gerald Boerner


JerryPhoto_8x8_P1010031 At the beginning of photography, two innovators offered very different options for creating these images on metal plates or paper without the need of an artist. The Daguerreotype, introduced in France by Louis Daguerre in 1839, created a positive image on a polished plate coated with silver. These images created strikingly sharp photos of people and landscapes. About the same time, William Henry Fox Talbot, in the United Kingdom, started creating negative images on silver-coated paper; positive images were created using “salt paper” and direct sunlight.

The process created by Fox Talbot, the calotype, was more of a mechanical process and produced less distinct images until other innovators contributed better processing techniques for “fixing” the images with sodium thiosulfate; Hershel made this critical contribution. This resulted in progressively more clear images than previously, being about equal to the Daguerreotype.

Most processes after 1855 used this two-step and the new wet-plate collodion process became standard. This advancement was a direct result of the previous developments of the calotype. From this point, the photograph became more lifelike, faster, and sharper than that produced by either the Daguerreotype or the Calotype. The durability of the images were also enhanced through the use of this two-step process.  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


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.



Early Photographic Technique: The Calotype

Latticed_window_at_lacock_abbey_1835 Calotype or talbotype is an early photographic process introduced in 1841 by William Henry Fox Talbot, using paper coated with silver iodide. The term calotype comes from the Greek καλό for ‘good’, and τύπος for ‘impression’.

The sensitive element of a calotype is silver iodide. With exposure to light, silver iodide decomposes to silver leaving iodine as a free element. Excess silver iodide is washed away after oxidizing the pure silver with an application of gallo-nitrate (a solution of silver nitrate, acetic, and gallic acids). As silver oxide is black, the resulting image is visible. Potassium bromide then is used to stabilize the silver oxide.

In the case of salted paper, the sensitive element is silver chloride formed when the salt (sodium chloride) reacts with silver nitrate. Silver chloride decomposes when in contact with light forming silver and chlorine evaporates. Excess silver chloride is washed out of the paper and the silver oxidizes in contact with gallo-nitrate. The silver oxide is stabilized on the paper with hyposulphite of soda.

Silver chloride is sometimes favored over silver iodide because it is less sensitive to temperature. During long exposures in direct sunlight the temperature on the paper can be quite high.

William Henry Fox Talbot

William_Henry_Fox_Talbot,_by_John_Moffat,_1864 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-barreled 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.

Thomas_Duncan,_1807_-_1845 Thomas Duncan, by Robert Adamson
and David Octavius Hill, about 1844;
medium: calotype print, size:
19.60 x 14.50 cm; from the
collection of the National
Galleries of Scotland

Talbot engaged in photographic experiments beginning in early 1834, well before 1839, when Louis Daguerre exhibited his pictures taken by the sun. After Daguerre’s discovery was announced (without details), Talbot showed his five-year old pictures at the Royal Institution on 25 January 1839. Within a fortnight, he freely communicated the technical details of his photogenic drawing process to the Royal Society. Daguerre would not reveal the manipulatory details of his process until August. In 1841, Talbot announced his discovery of the calotype, or talbotype, process. This process reflected the work of many predecessors, most notably John Herschel and Thomas Wedgwood. In August 1841, Talbot licensed Henry Collen, the miniature painter (1798-1879) as the first professional calotypist. Talbot’s original contributions included the concept of a negative from which many positive prints can be made (although the terms negative and positive were coined by Herschel), and the use of gallic acid for developing the latent image. In 1842, for his photographic discoveries, which are detailed in his The Pencil of Nature (1844), he received the Rumford Medal of the Royal Society.

How to make a calotype

You need two soft brushes, several vials, white watercolor paper preferably without watermarks, silver nitrate, potassium iodide, acetic acid (33%) and gallic acid (100%) a warm plate and a copying frame that consists of a wood or metal board covered by a piece of glass.

Whenever you are involved in this procedure you should wear protective goggles, an apron and gloves. If you are allergic to iodine, silver or potassium you should not try this.

Do all photosensitive work in a dark room, dim light (about a candle’s worth) can be used during processing. This process is quite insensitive to red and brown safe lights.

Whilst in plain daylight you can mix 6.5 grams of silver nitrate with 170 ml of water. Put the silver nitrate into the water, close the bottle and shake well until mixed.. It helps to heat the water a little. To make the results a little more consistent, distilled water should be used. Now put 57 grams of potassium iodide in 1000 ml of water and mix until totally dissolved.

Take a soft brush and "paint" the paper with the silver nitrate solution, made from a one to one mixture of the above compounds, until it is completely covered by it. Blot and dry the paper until it is only a little humid. Now put the paper into a tray with the potassium iodide solution for 2 to 3 minutes. Drain it, rinse it, blot it and dry it.

Talbot called this product iodized paper. Iodized paper can be stored indefinitely if it is in a dark and cool place. Be careful with the rinsing water, especially when rinsing silver nitrate. The first rinse should be done in a tray and the contents of this tray disposed in the same way as standard photo fixing agents. If in doubt call the environment protection office in your town.

You cannot use iodized paper to make pictures. It is not sensitive enough. To sensitize it you need a solution of 6.5 grams of silver nitrate, 57 ml of water and 10 ml of acetic acid and you also need another solution consisting of 100 ml of water and 1g of gallic acid. These solutions last for a unlimited time as long as they are not mixed.

Mix the above solutions in a relation 1:1 to have what Talbot called gallo-nitrate of silver. This solution can be kept for about a month in absolute darkness. Shortly before using the paper "paint" the coated side with gallo-nitrate, let it settle in for a few minutes and then rinse the paper in water. Blot and dry it. As soon as the paper passes from wet to humid your image media is ready to be used. It can also be dried and stored for a few days in absolute darkness.

If you kept to the formula the sensitivity of this medium should be 6/3 ISO but has the strange property of getting more sensitive the longer it is stored.

Once you have exposed your media in the camera you have to develop it immediately. To do that you brush some gallo-nitrate over it and warm it on the warm plate or with a blow drier. Do that until you have a detailed negative of your image. Once you are satisfied with the result rinse the paper in water, blot it and put it into the potassium bromide solution for a few minutes, after that rinse and dry. Now you should have your first calotype. Sometimes these were waxed to make them more transparent. Using carbon drawing fixer (you can get them at an artist’s supply store) helps the durability (If none is available cheap hair spray does the trick).

Now you have to get that nice negative into positive. To do that you can use calotype paper. Put it into the copying frame and your calotype face down on it. Now put your copying frame out in the sun for about 10 minutes (on a cloudy day make it 20). Develop your calotype as before and you should have a nice picture.

Copies on so-called salted papers give much better results. To do that first dip the paper in a solution of 100 grams of salt (no matter if sea salt or rock salt) in 1 liter of water. (If you live near an ocean you can also use seawater). Results are better if you add a pinch of sodium bicarbonate. Dry the paper and prepare it as before. Expose in the frame for about 10 minutes.

When opening the frame in dim light a photograph should be visible. Rinse the print in water for about 20 minutes. A second gallo-nitrate treatment is needed before exposing it to the light and you should fix it in sodium hyposulfite (about 10 grams per 100 milliliters of water) for about ten minutes and water again.

In Talbot’s original instructions, there is no mention made of hyposulphite of soda as a fixing agent; that was first used by John Herschel in February 1840.

Origins of the Calotype Concept

A young English gentleman on his honeymoon sat sketching by the shore of Lake Como early in October 1833, one eye pressed close to a camera lucida. With this simple draftsman’s aid, consisting of an adjustable metal arm fastened at one end to the artist’s sketchbook or drawing board and supporting a glass prism at the other, the young man saw a refracted image of the Italian landscape superimposed as if by magic on the pages of his sketchbook. It seemed a simple task to trace the features of the village buildings, lake, and distant mountains with his pencil. But alas, it only seemed simple, he later recalled, "for when the eye was removed from the prism—in which all looked beautiful—I found that the faithless pencil had only left traces on the paper melancholy to behold."

The would-be artist was William Henry Fox Talbot (1800–1877). A graduate of Trinity College, Cambridge, and a recently elected Liberal member of Parliament in the House of Commons, Talbot was a true polymath. His intellectual curiosity embraced the fields of mathematics, chemistry, astronomy, and botany; philosophy and philology; Egyptology, the classics, and art history. He had published four books and twenty-seven scholarly articles on a variety of subjects and was a fellow of the Astronomical, Linnean, and Royal Societies. Amid shopping lists and daily reminders, he filled his pocket diaries with the titles of books to read, complex mathematical formulas, and notations of experiments and experiences.

Gno_nega Modern Calotype by Alf B. Meier.
The horizontally reversed negative
of the Garden Gnome

Talbot’s frustration that day with the camera lucida led him to recollect his experiences ten years earlier with another drafting aid, the camera obscura—a small wooden box with a lens at one end that projected the scene before it onto a piece of frosted glass at the back, where the artist could trace the outlines on thin paper. The camera obscura, too, had left Talbot with unsatisfactory results, but it was not his own feeble drawings that he remembered after a decade. Rather he recalled with pleasure "the inimitable beauty of the pictures of nature’s painting which the glass lens of the Camera throws upon the paper in its focus—fairy pictures, creations of a moment, and destined as rapidly to fade away." These thoughts in turn prompted Talbot to muse "how charming it would be if it were possible to cause these natural images to imprint themselves durably, and remain fixed upon the paper." "And why should it not be possible?" he asked himself. Talbot jotted down thoughts about experiments he could conduct at home to see if Nature, through the action of light on material substances, might be brought to draw her own picture.

Garden GnomeModern Calotype by Alf B. Meier.
Garden Gnome, about 8×10"exposed
about 5 min at f/11, 1995, printed
on salted paper.

In January 1834, Talbot returned home to Lacock Abbey, an amalgamation of buildings incorporating the thirteenth- and fourteenth-century remains of a former abbey about eighty-five miles west of London. Within a few months, he began to experiment with the idea that had occurred to him at Lake Como and soon found that a sheet of fine writing paper, coated with salt and brushed with a solution of silver nitrate, darkened in the sun, and that a second coating of salt impeded further darkening or fading. Talbot used this discovery to make precise tracings of botanical specimens: he set a pressed leaf or plant on a piece of sensitized paper, covered it with a sheet of glass, and set it in the sun. Wherever the light struck, the paper darkened, but wherever the plant blocked the light, it remained white. He called his new discovery "the art of photogenic drawing."

As his chemistry improved, Talbot returned to his original idea of photographic images made in a camera. During the "brilliant summer of 1835," he took full advantage of the unusually abundant sunshine and placed pieces of sensitized photogenic drawing paper in miniature cameras—"mouse traps," his wife called them—set around the grounds to record the silhouette of Lacock Abbey’s animated roofline and trees. The pictures, Talbot wrote, "without great stretch of the imagination might be supposed to be the work of some Lilliputian artist."

Occupied with other activities, Talbot worked little on his invention between the sunny days of 1835 and January 1839, when the stunning news arrived that a Frenchman, Louis Daguerre, had invented a wholly different means of recording camera pictures with dazzling precision on metal plates. Preempted just at the moment when he was beginning to revisit his earlier experiments with an eye toward publication, Talbot scrambled to stake a claim to priority, to produce pictures that might compare favorably with Daguerre’s, and to solve the problems of lengthy exposure times and fugitive prints. Well before Daguerre revealed the details of his process, Talbot presented his own before the Royal Society in January and February 1839. At the time of Talbot’s announcement, his "art of photogenic drawing" was clearly better suited for recording the shadows of plant specimens, lace, or similar flat objects by direct contact—pictures we would now describe as photograms—than for camera images.

Although such photogenic drawings were beautiful as objects and useful as scientific records, Talbot knew that a fast, permanent, and accurate means of producing photographic images in the camera was the true brass ring, and on September 23, 1840, he found a way to seize it. Talbot discovered that an exposure of mere seconds, leaving no visible trace on the chemically treated paper, nonetheless left a latent image that could be brought out with the application of an "exciting liquid" (essentially a solution of gallic acid). This discovery, which Talbot patented in February 1841 as the "calotype" process (from the Greek kalos, meaning beautiful), opened up a whole new world of possible subjects for photography.

[ Source: William Henry Fox Talbot (1800–1877) and the Invention of Photography | Thematic Essay | Heilbrunn Timeline of Art History | The Metropolitan Museum of Art ]

The Calotype Process

The Calotype was a positive/negative process introduced in 1841 by Fox Talbot, and popular for the next ten years or so. Strictly speaking the term refers only to the negative image, but it is commonly taken to mean both.

A piece of paper was brushed with weak salt solution, dried, then brushed with a weak silver nitrate solution, dried, making silver chloride in the paper. This made it sensitive to light, and the paper was now ready for exposure. This might take half an hour, giving a print-out image. It was fixed in strong salt solution – potassium iodide of hypo.

Fox Talbot, who devised the process, showed his results at the Royal Institution on 25 January 1839, delivering a paper on the last day of that month.

The following year Fox Talbot succeeded in improving the "photogenic drawing" process, renaming it the calotype. He discovered that if he added gallic acid, the paper became more sensitive to light, and it was no longer necessary to expose until the image became visible. With further treatment of gallic acid and silver nitrate, the latent image would be developed.

In 1844 Fox Talbot opened a photography establishment in Reading in order to mass produce prints.

To make a print, the negative was placed on top of more photo paper, laid flat in a glass frame, and allowed to develop in sunlight.

The Calotype process was not as popular as its rival one, the Daguerreotype. There were various reasons for this:

  • its popularity was to a great extent arrested by patent restrictions;
  • the materials were less sensitive to light, therefore requiring longer exposures;
  • the imperfections of the paper reduced the quality of the final print; Calotypes did not have the sharp definition of daguerreotypes.
  • the process itself took longer, as it required two stages (making the negative and then the positive);
  • the prints tended to fade.

One might also suggest that the fact paper was used as a negative lessened the detail of the picture, though from an artistic point of view some would regard this as a desirable feature.

However, the calotype also had its advantages compared with the daguerreotype:

  • it provided the means of making an unlimited number of prints from one negative;
  • retouching could be done on either negative or print;
  • prints on paper were easier to examine, and far less delicate;
  • the calotype had warmer tones.

When the Collodion process was introduced in 1851, the calotype became obsolete. However, the negative-positive process was one day to become the standard photographic one, which is still used today.



Background and biographical information is from Wikipedia articles on:

Wikipedia: Calotype…

Wikipedia: William Henry Fox Talbot…

Web Sites and Blogs:

Heilbrunn Timeline of Art History: William Henry Fox Talbot (1800–1877) and the Invention of Photography…

Leggat’s Photo History: The Calotype Process…

Brainy Quote: Photograph Quotes…