Ancient ways, modern views

Calotypy for the 21st Century; Pt1: Dr Hugh Diamond’s Single Solution Process: Christopher Wright gives us a history of Calotypes and explains the process.

Writer and photography / Christopher A. Wright

History of calotypes

Note Dame, a photograph made using the Calotype process by Christopher Wright
Note Dame, a photograph made using the Calotype process by Christopher Wright.

One hundred and seventy years ago, announcements and adverts were made in European publications written for the new breed of specialists emerging from a world of multi-talented and broadly-educated polymaths and artists. Although the chemical reaction of silver salts with sunlight had been known since the days of the great Islamic and Judaic naturalists, the preservation of any image created by this interaction was stymied by the lack of a mechanism with which to stop the tarnishing process when it had reached a satisfactory level, where a recognizable image could be frozen in situ, and – if at all possible – made repeatable so that others might see and experience what the original view had been. The level at which realism had become a signature of art, such as in engraving, was well-known, for even this medium requires long and tedious hours of delicate handwork to copy details, as well as opening the door to interpretations and “corrections” which may or may not have existed in the original drawing from which the engraving was made.

English scientist Humphrey Davy (1778-1829) and potter Thomas Wedgwood (1771-1805) both made experiments using silver salts but were stopped in their researches by the same problem: an agent with which to stop the tarnishing (blackening) action of the silver salt and at the same time to remove successfully the unexposed silver so as to leave behind a recognizable image. While making similar experiments, English polymath William Henry Fox Talbot (1800-76) and brilliant French artist and theatric entrepreneur Louis Jacques-Mande Daguerre, ran into the same problem, but made the first significant breakthrough with the use of a strong solution of salted water to halt the development of the silver and to “wash away” the unexposed silver salts. In 1840, Sir John Herschel (1792-1871), scientist and son of the famous German-born astronomer and telescope-maker, Sir William Herschel (1738-1822), discovered sodium thiosulfate to be a solvent of silver halides in 1819, and in 1840, informed both Talbot and Daguerre of his discovery that this “hyposulfite of soda” (“hypo”) could be used as a photographic fixer, to “fix” pictures and make them permanent, after experimentally applying it in early 1839. His ground-breaking research on the subject was read at the Royal Society in London in March 1839 and January 1840.

Note Dame Calotype print by Christopher Wright
Note Dame Calotype print by Christopher Wright

In 1839-41 in Europe, while Henry Talbot and Louis Daguerre ran neck and neck to promote their versions of “photography” — it turns out this is a term originally invented by French-Brazilian businessman, experimenter and painter Hércules Florence (1804-1849) who not only conceived of the term, but also invented the “negative-positive” form of traditional image-making in 1833-4, before either Talbot or Daguerre had turned their attention to the problem and before Herschel claimed to have invented the terminology. Although Daguerre’s process was a financial success, supplanting the occupation of “miniature portrait painting” with his “mirror with a memory,” nonetheless, by the mid-1860’s, the daguerreotype was pretty much obsolete, having been replaced by the negative-process of wet-collodion announced by Gustave Le Gray and Frederick Scott Archer in 1850-1. Furthermore, the introduction by Blanquart-Evrard of a greatly simplified wet-paper Calotype and “albumenized paper” positive print processes in 1847 brought Photography into even greater public awareness.

After initial success with his “Photogenic Drawing,” or what is known today as “salted paper prints,” Talbot turned his attention in 1840-1, to making successful images in the camera obscura. His intention had been to make repeatable images which could be used successfully in the printing industry, to replace the tedious and difficult process of engraving. (In contrast to his “competitors,” Talbot was no artist, as his efforts with the camera lucida made in 1836 amply demonstrate. He had intended to overcome his inability in “capturing the fairy pictures which flitted before his eyes” by using salts of silver imprinted onto sheets of paper.) Photography in this negative-positive process was then halted in its development by Talbot’s insistence on placing heavy restrictions and expensive fees through the use of patents, in which he literally “stole” the inventions and discoveries of others to build up his own case. Examples of such piracy took Talbot to court a number of times, for example, to explain his use of Reverend Reade’s use of gallic acid as an accelerant in the sensitizing stage as well as a developing agent after exposure. He also claimed precedent use of sodium thiosulfate (“hypo”) as a fixative agent, even though his friend and fellow-collaborator/inventor Sir John Herschel had liberally given the use of this compound to both Daguerre and Talbot. As a consequence of these patent restrictions as well as the difficulty of the original process, the Calotype (so named by Talbot, from the Greek meaning “beautiful picture,” but better known in Great Britain as the Talbotype), languished in most of the world, save in Scotland, where there were no patent restrictions, producing a period (1843-8) of exceptionally beautiful portrait images by artist David O. Hill (1802-70) and chemist and photographer Robert Adamson (1821-48).

Calotype by Christopher Wright
Pathways in the Woods by Christopher Wright

Although the Calotype was restricted in France by patent, Talbot made a tour to promote his process, which lead several chemists and artists to take it up and make improvements. The most significant of these was Louis Désiré Blanquart-Evrard (1802-1872), a cloth merchant in Lille, France. In 1847, he published a manual for the making of paper photographs, changing and improving the order and methods of applying the iodizing and sensitizing chemicals. In 1850, he developed and made extensive use of the albumen paper print, a process which would dominate the photographic industry for much of the rest of the nineteenth century. In 1851, he started a printing company, the Imprimerie Photographique, which, in contrast with the Talbot-Henneman effort at The Reading Establishment, employed large numbers of employees and produced significant numbers of prints of other photographers, by using a “developing-out” method of printing instead of Talbot’s uncertain “sun-printing” (also known as “printing-out”).

In the manual we offer here, we will be discussing several popular forms of the Calotype: an improved version of the Talbotype devised by Dr Hugh Diamond and given at a reading to the London Photographic Society in 1853; a version of the famous “dry-waxed paper” process of French painter-photographer Gustave Le Gray (1820-84) as offered by Scottish physician Dr Thomas Keith; and a version this writer devised when learning the Calotype processes through direct study of manuals of the period (1840-55). Because the first process may be the easiest to work with, we will begin with Dr Diamond’s Process, with some small improvements by the English painter Sir William Newton which I found to work quite well. After success with this process, we will then introduce and make accessible the other versions indicated above, thereby giving the serious experimenter a variety of approaches to this exciting manner of making truly “hand-made photographs,” using the simplest of materials in an easy-to-understand approach.

Pathways in the Woods in the Calotype process by Christopher Wright
Pathways in the Woods in the Calotype process by Christopher Wright

Although many early experimenters complained to Talbot that their attempts at making pictures according to his directions were largely unsuccessful, their lack of good result was due, initially at first, to problems with the paper base. English papers of the time were generally sized (a technique of using animal and plant by-products to give the paper “body” and stiffness) with gelatine, which when combined with the chemicals used, produced differing results according to the amount of sizing, the quality of the water used in the paper-making, as well as the quality of the cotton rag of which the paper was made. Oftentimes, bits of brass buttons and other non-cloth debris from the rags as well as from the machinery used, would become incorporated into the sheets of paper, thereby including contaminants which would spoil the efforts to make a clean useable image. In France, paper was generally sized with starch, and made at ancient mills which were known for their plentiful and clean water-supplies. Now, in the twenty-first century, experimenters have available papers which are guaranteed to be 100% cotton rag and free from contaminants. However, there are several types of paper which are to be avoided. First, is any kind of paper in which “consumer by-products” or “recycled” materials have been included. Think of these as the modern version of the “brass button bits” which plagued nineteenth century practitioners. A second issue is one that originates from efforts to have papers which can last for centuries, the so-called “archival” or “acid-free” papers. Most often, these papers have been manufactured using calcium carbonate, or other similar alkaline buffering designed to reduce the general acidity of the paper and thereby extend its lifespan. Unfortunately for the modern Calotypist, such buffers are also poisonous to the process, as a certain amount of acidity is required in the paper to make it work successfully. Oftentimes, a buffering agent will cause the paper to over-develop spontaneously, thus ruining what might have been otherwise a successful exposure. As a consequence of these issues, there are, as there were in the mid-nineteenth century, few choices of useable papers in the making of successful Calotypes.

Papers to use for the Calotype process

After over a year of experimentation using a variety of papers from the US and Europe, I found several papers which work best. Of course, the subject matter determines to a certain extent the type and thickness of paper to be selected. In his several manuals, Gustave Le Gray recommends using different weights of paper depending on whether the subject is a portrait or a landscape. When I examined the Calotypes of Le Gray’s contemporary and friend Henri Le Secq at the George Eastman House/International Museum of Photography, I found that for subject matter like still-life and monuments/statuary, when a long exposure was a necessity in order to capture every detail possible, a thick paper was chosen without exception. Long exposures, followed by long immersions in chemical baths and water washes, required a paper with a substantial body, little likelihood of tearing while wet, and a smooth (but not glazed) surface.

Although there are a number of current papers described as being 100% cotton, only a few are applicable to Calotypy. The choice to reject a paper is made largely on the basis of the “additives” included to make the paper “archival.” Any paper which is buffered with calcium carbonate must be rejected; the alkaline chemical will cause a spontaneous and premature print-out effect, spoiling the paper and its image. The best we found for our own process are those with starch sizing and which are sturdy enough to withstand the stresses of the numerous chemical and water immersions the process requires. To make things as simple as possible, out of a stable of a dozen or so, I selected Crane’s Kid Finish and Southworth’s Resume for heavier stock (as well as for positive print-making); Clearprint 1000H and Mars Vellum for lighter weights.

Materials needed for the calotype process


  • Negative paper: Clearprint 1000H (National Printfast is the same paper under different name), Mars Vellum, 8-15 lbs (these papers need to be sized before use); or, because the above papers are not sized, use: Southworth Exceptional Thesis, 20 lb.
  • Positive paper: Southworth Resume and Crane’s Kid Finish, 24-32 lb
  • Bibiluous Paper: Viva paper towels (no pattern)
  • Blotting Paper: Cosmos Blotter
  • Beeswax: white; I purchased from a local beekeeper who provided me with both the common yellow and a pure white wax. Check your local Farmer’s Market; choose the cleanest product, without bits of comb or body-parts.


  • Distilled Water – 2-4 ltrs
  • Silver Nitrate – 1 oz
  • Barium Chloride -.5 oz
  • Potassium Iodide – 1 oz
  • Potassium Bromide -.5 oz
  • Iodine Crystal – 1-2 grms
  • Glacial Acetic Acid – 1 oz
  • Gallic Acid -.5 oz; or Ferrous Sulphate – 1 oz
  • Sodium Thiosulfate (“Hypo”) – 1 lb
  • Mucilage – 10% Gum Arabic – 1 oz

Equipment needed

  • Scales and Weights
  • Glass Labware:
    • (2) Beakers, 50 ml.
    • (1) Beaker, 150-200 ml.
    • (1) Beaker, 600 ml.
  • Glass Mortar and Pestle
  • Glass Developing Slab (window or plate glass, with filed and smoothed edges)
  • Glass Slabs to fit in dark-slide
  • Glass rods for spreading solutions on paper
  • Glass bottles:
    • (1) 500ml clear glass for double iodide solution
    • (1) 100ml amber for sensitizing solution
    • (1) 600 clear glass for sizing solution
  • (6) Sheets of masonite or foam-core board, cut to size of paper
  • Plastic clothes-pins to pin paper down
  • Portfolio: to contain blotting paper, sensitized sheets, etc.
  • Trays:
    • (3) new Cesco trays, with a piece of window glass cut to fit the bottom of the tray;
    • (2) one size larger than paper;
    • (1) large tray for rinsing, washing, etc.
  • Glass/plastic funnels on stand w/ unbleached coffee filters:
    • (1) for making “double iodide” solution
    • (1) for making aceto-gallic or aceto-iron developing solutions
  • Brushes: (4) “Hake” – 2-3″:
    • (2) for sizing and iodizing very thin papers
    • (1) for applying sensitizing solution
    • (1) for applying developing solution
  • Heating tray with (2) “ferrotyping” sheets for waxing negatives
  • Hard-rubber brayer

The process devised by Dr Hugh Diamond is easy and very straightforward; additionally it elegantly addresses a number of the drawbacks and faults which so frustrated the practitioners of the original Talbotype process.

Ancestors, a waxed calotype negative by Christopher Wright
Ancestors, a waxed calotype negative by Christopher Wright

In order to use the thinnest possible paper for making Calotypes, the usual approach (see, especially the chapters on making calotypes in Alan Greene’s Primitive Photography) is to size the paper with a thin starch sizing. Although this does work, I feel that it adds a step which can be a bit daunting to the beginner, a step which in the opinion and practice of miniature portraitist and well-known artist Sir William Newton, is also unnecessary. Newton’s approach, which I have found works quite nicely and avoids the necessity of a lengthy procedure over the kitchen stove, is to brush over the paper a dilute solution of barium chloride. After selecting pieces of 100% cotton, non-buffured and pH-neutral paper, free from pinholes or any appearance of unevenness in the texture (easily seen by holding the paper in front of a strong light), set these aside for treatment.

About 15 grains or a half-gram of the chloride is dissolved in 600 ml distilled water, and then brushed over the paper, which has been clipped to a piece of masonite or foamcore. The moistened paper is then laid flat to dry. Mark the back of the sheet with a small “x” so as to keep evident which is the side to be further treated, and which the side on which to make such notes as paper type, date and type of processing, subject matter and exposure data.

While the paper is drying, take sixty grains of silver nitrate and sixty grains of potassium iodide, and dissolve each separately in an ounce of distilled water. After these chemicals are thoroughly dissolved, mix and stir briskly with a glass rod so as to ensure their complete mixture. The chemicals will combine, forming a crystalline precipitate of silver iodide at the bottom of the beaker, and potassium nitrate in solution. Carefully pour off the liquid, and add several ounces of warm distilled water to wash the precipitate. Pour this water off and replenish several times to ensure a thorough cleansing of the silver iodide. Then pour into the beaker four ounces of distilled water, to which is added 650 grains of potassium iodide, which should be enough to re-dissolve the silver iodide and form a clear fluid. If this is insufficient potassium iodide to produce this effect, very cautiously add more, grain by grain until the fluid clears completely.

Taking one of the new trays with a cleaned and polished piece of glass covering the bottom, pour some of the silver iodide solution onto the glass, enough to cover about two-thirds of the sheet. Using a small slip of glass, carefully spread out the solution over the glass, making a layer of solution large enough to accommodate the piece of paper intended for a negative. Holding diagonal corners of the paper between thumb and forefinger of each hand, carefully lay the sheet on the solution so as to wet the bottom side as completely as possibly. Do not under any condition allow the solution to travel unto the upper side of the paper, as this will spoil the negative before it reaches the sensitizing stage. Again employing a chopstick (plastic or ivory) with a forefinger, carefully but quickly peel up the sheet and lay it, dry- (and marked-) side down, on a sheet of blotting paper. Then, quickly and gently swipe a clean glass rod several times over the wet side, so as to apply the silver solution evenly over the surface of the paper; this will also expel any air bubbles, ensuring a clean product free of spots.

Ancestors, a waxed calotype by Christopher Wright
Ancestors, a waxed calotype by Christopher Wright

After this iodizing stage, either pin the paper up or leave it lying on its blotter sheet until nearly dry. Then immerse the paper in a tray of cool common water for several hours, changing the water several times during this period of time so as to remove all the soluble salts. In addition, when there are several sheets of iodized paper in this tray of water, they should be agitated fairly often, to ensure that each sheet receive as thorough a coverage with water as possible.

After three or fours hours, the sheets may be removed from the water bath. They should show a pale straw or primrose color and be free from any unevenness of tint or density. When done properly, this paper can last for several years; however, if any unwanted soluble salts are left behind, the paper becomes brown and generally useless, due largely to attraction to atmospheric dampness.

When planning on a calotyping excursion, it is wise perform the above parts of preparation the evening before, saving the sensitizing stage for the early morning hours. To sensitize the paper and make it into a calotype negative, first prepare the “aceto-nitrate” solution: in an ounce of distilled water, dissolve 30 grains of silver nitrate and one drachm of glacial acetic acid. Mix thoroughly and store in a well-stoppered or capped amber glass bottle. To excite the paper, take ten drops (minims) of aceto-nitrate solution and mix this with three drachms of distilled water. (In his original directions, Dr Diamond follows more closely Talbot’s directions to add between six and ten drops of saturated gallic acid solution, but this more often than not leads to a short life-span and a strong tendency to “embrown” prematurely, sometimes even before the calotype has been exposed in the camera. Within the first decade of it’s use and following the advise of French photographers, Talbotype-calotype practitioners generally discontinued the use of gallic acid in the sensitizer, thereby giving their papers longer life and lessening the likelihood of the “embrowning” which so frustrated Talbotype-makers. In our experience, discontinuing the use of gallic acid in the sensitizing solution is a step in the right direction and makes greater the likelihood of success.)

Guided by a dark red safelight (No. 1A is a good choice), pour the solution through an untreated coffee filter paper onto the center of a clean sheet of glass which has been set on a level surface, and distribute the liquid over the glass’s surface with a slip of clean glass, over an area sufficient to moisten the entire sheet of iodized paper evenly and thoroughly. Float the iodized sheet on top of the pool of solution, until all the liquid has been completely and thoroughly absorbed. Carefully lift the sheet off the glass and, laying the dry side on a piece of blotting paper, draw a clean glass rod over the sheet several times, lightly and back and forth, until the fluid is evenly distributed on to the now-sensitized negative paper. It is at this stage that we have a “Calotype,” a paper negative suitable for use in the camera.

While the sensitized sheet is still damp, lay it on the piece of glass which is to go into the camera plate holder. At this time, it is a good idea to apply a thin edging of mucilage (10% gum arabic) to one edge of the paper; the paper will then dry flat and be fixed so as not to slip around or become rippled against the glass. It is now ready for exposure in the camera.

Depending on the subject matter and the intensity of the ambient light, as well as the chosen lens’ aperture, an exposure may take from two to five minutes at f5.6 using a normal or wide-angle lens for a light-colored monument or statue to 30-40 minutes at f22 for a forest view taken with a long focal-length lens.

After exposing one’s prepared selection of calotypes, the next step is to develop them in a suitable darkroom. Again, using red safelight illumination (I like using a rectangular safelight with a 5×7″ piece of red No 1A glass, over which I hold the developing slab so that I can more easily see the progress of development), I prepare two containers of developing solution, the first of saturated gallic acid in solution, and the second of gallic acid in which a few drops of aceto-nitrate have been added. First, I cover the leveled slab of glass with gallic acid alone, and let the paper become thoroughly saturated. There will be some development of the image, depending on the amount of image exposure in the camera, but the contrast and density will tend to be rather thin when developed with gallic acid alone.

After five minutes or so floating on gallic acid, pour off the used solution and, after rinsing the glass, pour on some of the second developer. Let this developer work on the paper for about five minutes, to build up contrast and density; then pour this solution off and again rinse the glass. Finally, cover the glass with gallic acid alone and let the negative develop for fifteen to forty minutes, at which point the shadow details will be fully brought out as well as those in the highlights. As mentioned above, the progress of developing may be watched by holding the developing slab over a small red safelight until just before the shadow detail begins to fog over. Practicing on duplicate negatives will train the eye to recognize the various stages of development, and before long, spoiled over- or under-developed negatives will be a thing of the past.

When the negative is fully developed, carefully remove it from the glass (the paper will likely be quite fragile from the long immersion in the various solutions, so extreme caution is advised), and immerse it into a clean wash-tray. Let the negative wash for ten to fifteen minutes, with several changes of clean common water, after which immerse the calotype into a tray of 15% sodium thiosulfate (hypo). With frequent but gentle agitation, “fix” the negative until any trace of the yellow coloring of any remaining silver iodide is gone and the clear areas are transparent and colorless.

After sufficient time in the hypo, re-immerse the calotype into the wash-tray and let it remain submerged for up to two hours, changing the water every twenty minutes or so, to ensure complete removal of any residual hypo.

The negative may be dried and prints made from it as is, but better positives may be made by waxing the negative first. The procedure is, again, easy and straight-forward. Using a warming-plate, on top of which is placed a fresh clean ferrotyping plate on which one rubs a block of white beeswax until the plate is fairly well covered with a thin but even coating. Lay the dry calotype on this melted wax, and rub more wax on top of the paper, until the calotype is pretty well coated on both sides. There will likely be an excess of wax, which may be removed by laying a sheet of blotting paper both under and on top of the negative and rolling a hard rubber brayer over both sides until there are no more shining spots evident on the calotype.

Printing positives will be easier and faster when made from a waxed calotype than from one which has not been so treated.

Thus ends our first lesson on making the primitive paper negatives called Calotype, using modern materials as much as is possible. In our next installment, we will introduce the Dry Waxed Paper Process (Papier Ciré Sec) invented by the brilliant, productive, inventive if eccentric painter-turned-photographer, Jean-Baptiste Gustave Le Gray (1820-84). The hey-day of the Dry Waxed Paper Process in both France and Great Britain matches Le Gray’s period of commercial and personal success (1850-60), during which he also gave the photographic world both the highly successful wet- and dry-plate collodion-on-glass negative processes, as well as methods of toning albumen prints with salts of gold, producing exquisite tones of purple and brown as well as using sulphuric acid to produce his signature “bistre” coloration. Le Gray’s dry waxed paper process will be introduced by Dr Thomas Keith, who simplified Le Gray’s somewhat unnecessarily complex chemistry, giving the amateur an easier method for making successful and long-lasting calotype negatives.


  • Croucher, J.H. and Le Gray, Gustave: Plain Directions for Obtaining Photographic Pictures; NY: Arno Press, 1973, reprint of 1853 edition.
  • Blanquart-Evrard, Louis Désiré, Traité de Photographie Sur Papier; Paris: Librairie Encyclopédique de Roret, 1851.
  • Delamotte, Philip H., F.S.A.: The Practice of Photography on Paper and on Glass: A Manual; NY: Office of the NY Photographic and Fine Art Journal, 1854.
  • Hunt, Robert: A Popular Treatise on the Art of Photography…; Glascow: Richard Griffin and Co., 1841.
  • Le Gray, Gustave: Advantages of the Waxed Paper Process (trans by Geo Knight fr 1854 edition); (n.p.): Geo Knight & Co., eds., 1854.
  • Sparling, W.: Theory and Practice of The Photographic Art, etc.; London: Houlston and Stoneman, 1846.
  • Sutton, Thomas, BA.: The Calotype Process. A Handbook to Photography on Paper; (London): Jos Cundall, 1855.

Christopher Wright has been making large-format photographs since 1980. Born with a very rare connective tissue disease, nonetheless Wright has degrees in languages and in History of Religions. He is self-taught in photography, and since 2000, has used grants to learn and to put into practice such antique processes as Calotype, Collodion (wet and dry); salted and albumen prints, argentotype, and energiatype.

8 thoughts on “Ancient ways, modern views”

  1. One of the best explanations of the Calotype process that I have read.
    Thank you Chris for directing me to this very well-written and expertly explained method of the early photographic process.

  2. Really interesting description of a traditional photographic process.
    However there might be a problem with the ingredients’ data, or the recipe:
    1oz potassium iodide is necessary. Then 650grains of potassium iodide is added to 4ozs of distilled water. That potassium quantity equals to 1,354 ozs.
    Could somebody, who tried the process, help with this? (Is it perhaps 65grains or 6,50grains?)

  3. I was very sad when most of the color labs in LA, CA shut down and went to digital. I basically did the same and went digital myself building custom servers, repair, fix, the PCs people use for imaging. I miss the chemistry and was thinking that this not so lost art might be something to pick up as I retire. Thanks for all of the great information. One more thing.. People ask me why I liked the photo-biz so much? I was fortunate to work in a lab in Brentwood, a very upscale neighborhood next to Bel-air. I could never afford to take the trips and see the things they saw but I realized I did. I did it through their photos. I started on a Noritsu running about 120 rolls a day and worked my way to poster size and larger as I progressed. If didn’t love it, I wouldn’t have done it as the pay was not the greatest. The photographers were making all the money although I sold many tinted infra’s at art festivals to make ends meet. Once again, thanks.


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