HISTORICAL NOTE

phalt, called bitumen of Judea, which had been known as an etching base since the Pretty As APicture days of Rembrandt (mid-1600s). Bitumen of Judea hardened on exposure to light, and so proved ideal for capturing images Pari 1: Materials for that would also withstand the etching process for metal lithographic plates. Black-and-White Niepce coated a pewter plate with the asphalt solution, then exposed it through a crude camera to an outside image under bright sunlight. The brightly lit areas of the The advent of photography and photo• BULLETIN), Wedgewood made silhouette image hardened the asphalt, while the graphic materials profoundly affected not images by placing leaves and other natural shadows remained soft and soluble. Re• only scientific research but our view of his• objects on top of the sensitized paper-but moving the soft (or unexposed) asphalt tory, law, and daily life. For science, photo• he had no way to stop the exposure or "fiX" with a solvent of lavender oil, Niepce was graphic materials capture permanent the image by dissolving ·away the unex• left with a metal plate on which all the light images of experiments and phenomena. posed silver salts, and the image turned areas bore a raised coating of the hardened Photographic materials can integrate in• completely dark in a short time. bitumen, while the rest was bare metal. coming light over time and record events The demand for inexpensive, quick; but After etching the resulting pewter plate too faint or too rapid to be seen by the hu• realistic portraits caused 19th cerituiy art• with acid, the plate could then be printed man eye, or at wavelengths beyond the ists and entrepreneurs to look for ways to by the ordinary lithographic printing visible range. solve the problem. Some artists created sil• presses of the day. Niepce's first success is This year, 1989, is the 150th anniversary houettes, projecting a shadow of their sub• a blurry of the barnyard taken of the rise of the daguerrotype process, the ject onto a drawing surface and then filling from a window of his country estate in first widespread black-and-white photo• in the outline. Lithography, the technique 1826. He called his technique "heliogra• graphic technique that created "pictures" of drawing an image by hand onto a pre• phy" because of the need for bright sun• of the world without requiring the skill and pared stone surface, etching the stone with light. patience of a painter. This year is also the acid to allow the "undrawn" areas to ab• A French scenic painter, Louis Jacques centennial of George Eastman's introduc• sorb ink, and then printing the iinage onto Mande Daguerre, learned of Niepce's dis• tion of rolls of flexible photographic film paper, became popular around 1813. covery and approached him about forming plus the portable cameras to use them, a partnership. Daguerie had himself ex• which revolutionized photography and perimented unsuccessfully with silver made it available to the general public. This salts to record his scenes "by the spontane• month's Historical Note will look at the be• Bitumen of Judea ous action of light:' The two became part• ginnings of photographic chemistry and ners in DecemJ?er 1829. Niepce died four early materials for capturing black-and• [asphalt] hardened on years later, and Daguerre continued there• white images on metal or glass plates or on exposure to light, and search with Niepce:s son Isidore, riow re• sensitized paper. turned from his military service. Daguerre As early as 1565 some chemists had no• so proved ideal for eventually discarded the asphalt process ticed the blackening of silver salts on expo• capturing images that because of the coarseness of detail artd ap• sure to light or heat. In 1725 German proached the problem in different ways. physician Johann Heinrich Schulze placed would also withstand In 1835 he found that a polished silver stenciled letters over a mixture of silver ni• the etching process for plate exposed to .iodine fumes formed a trate and chalk, showing that the darken• light-sensitive layer of silver iodide. The ing was caused by light alone. Schulze, lithographic plates. plate exposed in a camera would produce a however, merely wanted to investigate an clear Image if it was then fumed with mer• unusual chemical phenomenon and did CUI)' vapor. The remaining unexposed sil• not attempt to develop it into a technique ver iodide was then removed by rinsing the for producing images. French inventor Joseph Nicephore plate in a strong solution of common salt In 1777 Swedish chemist Karl Wilhelm Niepce searched for a stone that would be and water. Daguerre himself claimed that Scheele exposed to a spec• perfect for lithography. Artistically untal• "with this technique, without any knowl• trum from the suli, and saw that blue and ented, Niepce had his son Isidore draw de• edge of chemistry or physics, one will be violet light produced a more pronounced tailed images onto his test surfaces. able to make in a few minutes the most effect than did red. Scheele also investi• Unfortunately, young Isidore was called detailed views:' gated the light-sensitive properties of other away to military service, and Joseph The "daguerrotype" process so im• silver salts; he determined the chemical ba• Niepce had ~o find some other way to draw pressed the French scientist Dominique sis for the phenomenon in silver chloride, images on his lithographic stones. With the Arago that Arago persuaded the French showing that light reduced the solution to help of his brother Claude, Niepce investi• government to give Daguerre and his part• metallic silver and free chlorine. gated photographic techniques using silver ner Isidore Niepce generous lifetime an• At the tum of the 19th century Thomas chloride. nual pensions of 6,000 and 4,000 francs, Wedgewood published the results of his They tested the light sensitivities of iron, respectively, if only they would grant free experiments treating leather and paper manganese, and other compounds, U$ing use of their discovery. with silver nitrate. Working with his part• stone, metal, and paper to support their Daguerrotyping proved to be a com• ner Humphrey Davy (see the Historical chemical coatings, or emulsions. Finally, plete success. Other backyard inventors Note in the January 1989 issue of the MRS they used guaiacum resin and then as- soon found various chemicals that im-

54 MRS BULLETIN/MAY 1989 HISTORICAL NOTE

proved the speed and resolution of the the silver deposits rested. The first news of the Ameri• process, and local daguerrotype artists be• Talbot's negative-to-positive approach is can Civil War and the Crimean War were came commonplace. the basis of modem photography. He taken by such photographers. By the mid- The typical daguerrotype was made named his process the ";' from 1850s, the wet- process })ad re• from a smooth copper plate, silvered and Greek for "beautiful picture." Talbot's placed both the daguerrotype and highly polished, which was then im• friend, astronomer Sir John Herschel, calotype. Because of the fine grain and mersed in iodine fumes, and then exposed named the discovery "photography:' high quality of negatives from wet collo• in a camera for several minutes. This Talbot's , while not as sharp as dion plates, this technique remained in use proved adequate for landscape photogra• daguerrotypes, could be copied over and until the mid-20th century. phy, but not for portraits-some early por• over again from the original negative pa• However, the need for preparing each trait subjects were made to sit absolutely per. Later improvements to the calotype plate before use and then developing im• motionless under blazing sunlight, their process included treating the sensitized mediately after exposure made the wet• faces coated with white flour, for minutes paper first with one or more layers of albu• collodion process inconvenient for most on end! men (egg white), which held the silver photography. Other improvements ap• A fresh daguerrotype could be devel• chloride deposits more on the surface of peared in the 1860s and 1870s, first with a oped over a cup of heated mercury, then the paper rather than sinking deep into the dry collodion process that had much of the rinsed in a solution of thiosulfate of soda fibers. Prints obtained from albumen• excess silver salts washed out of the hard• and darkened with another rinse of gold coated paper were yellowish, but could be ened emulsion before exposure. chloride. The image itself was made of a darkened to a deep sepia tone by treating In 1871 an English physician and ama• milky white amalgam of the mercury and the paper with gold chloride. Albumen pa• teur photographer, Robert L. Maddox, the nascent silver in the emulsion (show• per remained in common use until about suggested using gelatin instead of collo• ing the bright areas), with the dark areas 1900. dion as an emulsion on glass plates. This showing only the plain silver of the plate. proved successful, and within two years The original silver-coated copper plates Richard Kennett marketed packets of pre• were 6 1/2 by 8 1/2 inches. pared gelatin-based emulsions that pho• Since the daguerrotype was formed by tographers could dissolve in warm water reflected light in the camera, the resulting A fresh daguerrotype and coat their own plates. By 1875 com• picture was a "mirror image;' which could be developed over mercially prepared dry plates already caused some problems. Each daguer• coated with sensitive emulsion were avail• rotype was also unique and could not be a cup of heated mercury, able on the market. These ready-made copied. Though it was the first commer• then rinsed in a solution plates could be stored for months and cially used photographic technique and of thiosulfate of soda eventually years before a photographer immensely popular, daguerrotyping needed to use them. proved to have no real future in the devel• and darkened with Between 1873 and 1885 the photographic OP.ment of photography. journals were filled with accounts by ama• Working independently of Daguerre another rinse of teur experimenters working on ways to im• and Niepce, William Henry Fox Talbot, an gold chloride. prove the gelatin-based emulsions-the English archaeologist and philologist most important advance was the heating of trained at Cambridge, had discovered the gelatin before coating plates, or "ripen• many of the same principles before the first ing/' which further increased the sensitiv• publication of the daguerrotype process. English sculptor F. Scott Archer intro• ity to light and therefore lowered the He worked mainly with paper, washing it duced the use of wet collodion (nitrocellu• exposure times. in successive baths of salt water and silver lose, or dissolved gun cotton in a solution Next month's Historical Note will look at nitrate solution, which left a deposit of sil• of alcohol or ether) as a coating for glass the development of flexible plastic films as ver chloride on the fibers of the paper. He plates in 1851. The collodion solution con• supports for photographic emulsions, con• then exposed the still-wet paper in a cam• tained potassium iodide or ammonium io• tinuous roll films as used in the motion pic• era for several minutes until an image ap• dide and was allowed to stand until the ture industry, and the discovery of peared. collodion had set to a jelly-like consistency. pigmented and layered emulsions to pro• Talbot also made an extremely important In the dark, the coated plates were then duce color photographs. discovery-that a much shorter exposure immersed in silver nitrate immediately be• KEVIN J. ANDERSON (about 1/60th of that needed to make a visi• fore use, forming a light-sensitive layer ble image) would actually leave a "latent" within the pores of the collodion emulsion. About the Author: In addition to contribut• image on the sensitized paper. The latent The plates had to be coated, used imme• ing to the Historical Note section of the MRS image could then be "developed" in a solu• diately, and developed immediately. When BULLETIN, Kevin f. Anderson is also a tion of gallic acid. Talbot fixed, washed, the solvents evaporate entirely, collodion prolific science fiction writer. He has published and dried the paper, which contained a leaves a clear hard plastic-like film that is ooer 100 short stories, many of which have negative image. By waxing or oiling the impervious to water-and therefore imper• been nominated for 1najor awards or selected as negative sheet, he could make the paper vious to the chemicals needed to develop among the year's best. Two of his nooe/s were reasonably transparent, and if he then the image. recently published by Signet Books, Resurrec• made a second exposure through the first Collodion allowed exposure times short tion, Inc. (July 1988) and Gamearth (March paper onto another sensitized sheet, he enough to make the photographic process 1989). Tivo more nooels are forthcoming from produced a positive, though coarse and useful for recording real life. Photogra• Signet. He has recently been commissioned by grainy, image. The graininess of the image phers using wet-collodion plates traveled Bantam Books to write three additional nooels was caused by the poor transparency of the countryside carrying their own chem• in col/abomtion with plasma physicist and the paper and the coarse fibers on which istry sets and tent-like portable darkrooms. nooelist Doug Beason. 0

MRS BULLETIN/MAY 1989 55