by Gerald Boerner
The photographic printing processes that we have considered to this point have been based upon sensitizing a medium (glass, cooper, tin, or paper) with a binding solution and a sensitizing solution that included silver compounds. The silver medium was exposed to light, the excess silver removed through a washing process and the finished image was packaged or toned to protect the image. This was the typical process throughout most of the 19th century.
In the 1870s, however, different sensitizing processes were tried using light sensitive metals other than silver. These were discussed in yesterday’s post on the non-silver processes. Our technique today involves using an iron compound (ferrous oxalate) as the light-sensitive compound. This process, known as the Platinum Printing-Out Paper. This process converts the iron compound into a form that is highly stable and renders tonality to images that provides greatly-enhanced shades in the shadow areas as well in the mid-tone region.
This type of print has been used by some of the major photographers to produce very-artful prints that stand the test of time. These prints, when on exhibition, produce images far superior to those of the latter 19th/early 20th century. Even now, we cannot equal them in our darkrooms.
This is the first of a two part series. Today we will examine the process more generally and tomorrow we will examine some of the chemistry involved. Enjoy you exposure to this great imaging method.. GLB
“Twelve significant photographs in any one year is a good crop.”
— Ansel Adams
“While photographs may not lie, liars may photograph.”
— Lewis Hine
“Travel becomes a strategy for accumulating photographs.”
— Susan Sontag
“There’s a discipline. When you take someone’s portrait, you don’t have to take 50 photographs, just find that one so that when you release the shutter, that’s the image that you took.”
— Matthew Modine
“There’s no question that photographs communicate more instantly and powerfully than words do, but if you want to communicate a complex concept clearly, you need words, too.”
— Galen Rowell
“To take a photograph is to participate in another person’s mortality, vulnerability, mutability. Precisely by slicing out this moment and freezing it, all photographs testify to time’s relentless melt.”
— Susan Sontag
“We must carefully consider card security solutions, such as adding photographs or machine-readable electronic strips, so to prevent further breaches of individual privacy that could result from changes to the design of Social Security Cards.”
— Ron Lewis
“To take photographs means to recognize – simultaneously and within a fraction of a second – both the fact itself and the rigorous organization of visually perceived forms that give it meaning. It is putting one’s head, one’s eye and one’s heart on the same axis.”
— Henri Cartier-Bresson
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: Platinum Prints
Unlike the silver print process, platinum lies on the paper surface, while silver lies in a gelatin or albumen emulsion that coats the paper. As a result, since no gelatin emulsion is used, the final platinum image is absolutely matte with a deposit of platinum (and/or palladium, its sister element which is also used in most platinum photographs) absorbed slightly into the paper.
The first person to have recorded observing the action of lights rays on platinum was Ferdinand Gehlen of Germany in 1830. The following year his countryman Johann Wolfgang Dobereiner determined that the action of light on platinum was quite weak, but that perhaps something could be combined with platinum to increase its sensitivity. Through experimenting, he eventually found that ferric oxalate was the missing ingredient. The combination of these two metals is still the basis of the platinotype process in use today.
In 1832 Englishmen Sir John Herschel and Robert Hunt conducted their own experiments, further refining the chemistry of the process. In 1844, in his book Researches on Light, Hunt recorded the first known description of anyone employing platinum to make a photographic print. However, although he tried several different combinations of chemicals with platinum, none of them succeeded in producing any permanency in the image. All of his prints faded after several months.
Sir John Hershel
Sir John Frederick William Herschel, 1st Baronet KH, FRS was an English mathematician, astronomer, chemist, and experimental photographer/inventor, who in some years also did valuable botanical work. He was the son of astronomer Sir Friedrich Wilhelm Herschel and the father of 12 children.
Herschel originated the use of the Julian day system in astronomy. He named seven moons of Saturn and four moons of Uranus. He made many contributions to the science of photography, and investigated colour blindness and the chemical power of ultraviolet rays.
Herschel made numerous important contributions to photography. He made improvements in photographic processes, particularly in inventing the cyanotype process and variations (such as the chrysotype), the precursors of the modern blueprint process. He experimented with color reproduction, noting that rays of different parts of the spectrum tended to impart their own color to a photographic paper. He collaborated in the early 1840s with Henry Collen, portrait painter to Queen Victoria. Herschel originally discovered the platinum process on the basis of the light sensitivity of platinum salts, later developed by William Willis.
Unaware that the term photography had already been coined by Hercules Florence in 1834, Herschel also coined the term in 1839. He applied the terms negative and positive to photography.
He discovered sodium thiosulfate to be a solvent of silver halides in 1819, and informed Talbot and Daguerre of his discovery that this "hyposulphite of soda" ("hypo") could be used as a photographic fixer, to "fix" pictures and make them permanent, after experimentally applying it thus in early 1839. His ground-breaking research on the subject was read at the Royal Society in London in March 1839 and January 1840.
Developing the Platinum Printing Process
Over the next decade, Hunt noted that platinum prints he had left in the dark faded very slowly but gradually were restored to their original density. They eventually became permanent and, even more interesting, they shifted from a negative to a positive image.
By the early 1850s, however, other more reliable photographic processes, such as salt and albumen printing, had been developed and were beginning to be widely used. Those scientists who had previously conducted research on platinum lost interest in the process as other methods became more commercially viable. The only major advances in platinum research reported during that decade were made independently by C.J. Burnett and Lyonel Clark of Great Britain. In 1859 Burnett published an article in the British Journal of Photography describing his use of sodium chloroplatinate as a fixing agent. His modification of the platinum printing process resulted in prints that were reasonably permanent enough that he could exhibit them in public. That same year Clark also exhibited prints made using a slightly different process.
No notable advances were made during the 1860s, no doubt due to the rapid rise in the popularity of other processes. It was 1873 before the first patent for a platinotype process was granted, to William Willis (British Patent No. 2011, June 8, 1873). Willis introduced the "hot bath" method where a mixture of ferric oxalate and potassium chloroplatinate are coated onto paper which is then exposed through a negative and developed in a warm solution of potassium oxalate. This is the basic platinotype process which is in use today. In 1878 Willis was granted a second patent for a simplification of his initial process that eliminated the need for a hyposulfate (metabisulfate) bath. Two years later he received a third patent for further refinements to the process.
While Willis had greatly advanced the chemistry of the platinum process, by 1880 there was still no reliable method for the individual preparation of platinum paper. Two years later two Austrian Army offices, Giuseppe Pizzighelli and Arthur Baron V. Hubl, published a dissertation describing a straightforward process for preparing the paper. They continued their research for several years, and in 1887 Pizzighelli patented a new process that made the commercial production of platinum paper viable for the first time. The new process was briefly known as a "Pizzitype" and was marketed under the name "Dr. Jacoby’s Printing Out Paper."
Willis quickly countered this advance by obtaining two more patents in 1888 for cold-bath processes. By adding more platinum to the developing process, he produced prints that had dense brown-black shadows rather than the lighter browns that were the best previous processes could produce. While much more aesthetically pleasing, prints developed by this process were difficult to reliably produce.
Four years later he began manufacturing a platinum paper that was designed for the cold-bath process, and this became the standard for the rest of the decade. The business he started in 1880, called the Platinotype Company, rapidly expanded, and soon he was selling his paper throughout Europe and in the United States By 1906 his company had sales totaling US $273,715 ($6,510,362 in 2009 dollars), a significant amount at that time.
Seeing the skyrocketing demand for platinum paper, the Eastman Kodak Company in Rochester, New York, tried to develop its own line of paper starting in 1901, but they could not duplicate the quality of Willis’ product. Kodak then tried to buy Willis’ company, but he was not interested. Rebuffed, Kodak instead bought the relatively new company of Joseph Di Nunzio in Boston. Di Nunzio had developed a reasonably good platinum paper, which he sold under the name of "Angelo", and Kodak sold this paper for several years.
When Willis began marketing his paper platinum was relatively cheap, by 1907 platinum had become 52 times more expensive than silver. Eastman Kodak and most other producers stopped fabrication of the paper in 1916. Russia controlled 90% of the world platinum supply in World War I and all available platinum was used in the war effort.
In photography, palladiotype is a monochrome printing process, a rather obscure variant of the platinotype.
Due to the shortage of commercial paper and high cost, photographers experimented with palladium paper and platinum-palladium mixes. Platinum paper has continued in use until the present, interrupted only by the world wars.
The process was in use after World War I, because the platinum used in the fairly popular platinotype quickly became too expensive for use in photography. Photographers tried to replace the platinum with the much cheaper palladium which gave similar effects. The cost of this metal, however, started to rise too and eventually, around 1930 the process was abandoned in favor of more economical processes.
Characteristics of a palladium print, compared to a platinum print:
- A warmer tone;
- Easier to solarize (see: Sabatier Effect);
- Large tonal range, up to D= 2.1, thus requiring a contrast-rich negative for printing;
- Deeper blacks, with a higher maximum density;
- A softer image, with delicate highlights.
Platinum printing is based on the light-sensitivity of ferric oxalate. Ferric oxalate is reduced to ferrous oxalate by UV-light. The ferrous oxalate then reacts with platinum(II) or palladium(II) reducing it to elemental platinum, which builds up the image.
By varying the amount of platinum vs palladium and the addition of oxidizing chemicals such as hydrogen peroxide and potassium dichromate or potassium chlorate, the contrast and "color" of the final image can be modified. Because of the non-uniformity of the coating and mixing phases of the process, no two prints are exactly the same, adding additional "cachet" to a platinum print.
The inherent low sensitivity of the process is because the ferric oxalate is sensitive to ultra-violet light only, thus specialized light sources must be used and exposure times are many times greater than those used in silver-based photographic processes.
Due to the unavailability of pre-coated sensitized paper, all platinum/palladium printing is done on paper coated by the printer. The light sensitive chemicals are mixed from powdered basic chemicals, or some commercially available solutions, then hand applied with a brush or a cylindrical "pusher".
Many artists achieve varying effects by choosing different papers for different surface characteristics, including vellum, rag, and rice, among others – even silk. On the collecting market, platinum prints often sell for many times what a similar silver-gelatin print would sell for.
Platinum prints are loved by photographers and treasured by collectors and investors because of their tonal range, the surface quality and their permanence. The unique beauty of a fine platinum print involves a broad scale of tones from black to white. The delicate, rich platinum tones range from warm black, to reddish brown, to expanded mid-tone grays that are unobtainable in silver prints. In the deepest shadows the platinum print still presents information; the platinum whites are delicate and the depth of the image is alive and three-dimensional. Platinum prints are not only exceptionally beautiful, they are the most durable of all photographic processes. The platinum metals (platinum and palladium) are more stable than gold, and it is estimated that a platinum image, properly made, can last thousands of years.
Some of the most desirable characteristics of a platinum print include:
- An absolutely non-reflective surface of the prints compared to modern-day glossy prints
- A very delicate, large tonal range
- Not being coated with gelatin, the prints do not exhibit the tendency to curl
- The darkest possible tones in the prints are still lighter than silver-based prints. Recent studies have this attributed to an optical illusion produced by the gelatin coating on RC and fiber-based papers. Platinotypes that have been waxed or varnished will produce images that appear to have greater D-max than silver prints.
- A greatly decreased susceptibility to deterioration compared to silver-based prints due to the stability of the process and because they are commonly printed on 100% rag papers
Major Photographers Using the Platinum/Palladium Technique
The following is a partial list of the major photographers in the past one-hundred and fifty years who have used the platinum/palladium printing-out process. Those with recent exhibits (within the past ten years or so) at the J. Paul Getty Center Museum in Los Angeles. I have written reviews of some of these exhibits, as indicated by the [Exhibit Review] notation, and/or a profile of the photographer, as indicated by the [Profile] notation, behind the photographer’s name.
These photographers include:
- Alvin Langdon Coburn [Profile]
- Imogen Cunningham [Profile]
- Edward S. Curtis [Profile]
- F. Holland Day
- Frederick Evans [Profile][Exhibit Review in Preparation]
- Laura Gilpin
- Frederick Hollyer [Profile]
- Gertrude Kasebier [Profile]
- Tom Millea [Profile]
- Edward Steichen [Profile]
- Alfred Stieglitz [Profile]
- Paul Strand [Profile]
- Clarence H. White [Profile]
Background and biographical information is from Wikipedia articles on:
Wikipedia: Print Permanence…
Wikipedia: Platinum Prints…
Wikipedia: John Herschel…
Web Sites and Blogs:
Unblinking Eye: A Guide to Platinum Printing…
Alternative Photography: The platino-palladiotype process…
Brainy Quote: Photography Quotes…