What is a Tintype?
The year was 1851, and the earliest practitioners of photography were traveling chemists. They journeyed from town to town and from door to door, teams of horses drawing their mobile darkroom wagons—known then as photographic vans. These itinerant operators did more than merely produce likenesses; they created heirlooms forged in silver by the action of sunlight, articles destined to pass down through successive generations—historical artifacts of such permanence that a great many survive, unimpaired, to the present day.
Tintypes are formed by pouring a solution of silver collodion over sheets of blackened metal and exposing them to light. Being the work of the hand, and executed upon apparatus constructed more than a century ago, they bear small imperfections that contribute to their distinctive character. There is about them something ageless, something that does not yield to the passage of time. To regard a tintype is not the same as regarding a modern photograph, and no description can adequately convey the difference. One must see the object for oneself.
Long after paper photographs have yellowed or torn, and after selfies have evaporated into the cloud, the tintype will yet remain, unfaded. The wagons and the horses have disappeared, yet the chemistry has altered but little. By the employment of photographic methods once mastered and thereafter largely forgotten for more than a hundred and fifty years, we produce the same enduring pictures that were made in the days of the late war.
THE TECHNICAL PARTICULARS — IN GREATER DETAIL THAN SOME MAY DESIRE
Wet-plate collodion was invented in the year 1851 by Frederick Scott Archer. It is termed “wet plate” because the entire operation—from beginning to end—must be completed before the chemistry dries upon the surface. Plates of glass or metal are first coated with collodion, a viscous preparation composed of nitrocellulose dissolved in ether and alcohol. Physicians formerly employed collodion to seal minor wounds and secure bandages. The word itself derives from the Greek kollodis, signifying glue, and the substance grows adhesive as the volatile spirits evaporate. Archer was the first to perceive that salted collodion served more effectively than albumen—dried white of egg—as a binder to hold and sensitize silver nitrate, the chemical agent upon which the photographic process depends. That discovery marked the true coming of age of the art.
Once the collodion has been poured upon the plate, only a few moments elapse before it becomes tacky. The plate is then immersed, evenly and without hesitation, in a bath of silver nitrate—the sensitizing agent. Any irregularity in the immersion will later reveal itself as artifacting, which may prove agreeable in its own character. Such artifacting is one among the many small accidents, some of them fortunate, inherent in the process. The immersion permits the silver nitrate to combine with the various halides previously introduced into the collodion. The result is silver halide, rendering the plate sensitive to the blue portion of the spectrum—not the red—and for this reason a darkroom may be illuminated with red light without injury to the image.
Under that subdued light the plate is transferred from the silver bath into a light-tight holder, and thence into the camera. The operator has only until the plate begins to dry in which to complete his labor—ordinarily from five to fifteen minutes, according to the state of the weather. Time presses.
The instruments employed for the making of tintypes are known as view cameras. One has doubtless seen the old representations of them—a man bent over a large wooden chamber, a dark cloth drawn over his head. Such is a view camera: a hollow box bearing a small lens at its forward end. Indeed, a lens is not strictly required; a minute aperture alone will serve, in which case the apparatus becomes a pinhole camera. The image falls within the camera inverted and reversed, projected upon a sheet of ground glass by means of which the photographer composes and focuses. It is for this reason that tintypes appear reversed. Those who sit for them behold themselves as in a looking-glass.
A plate thus sensitized is but little sensitive by present standards—approximately of the order of ISO 1. Consequently the exposures are protracted, ranging from a single second to several minutes. No countenance can sustain a genuine smile for the space of ten seconds, and this accounts for the absence of smiles in the photographs of that distant time. We now possess powerful lamps that abridge the exposure, yet portraits made by natural light enjoy no such advantage. The sitter must remain perfectly still for some seconds at the least, and must do so in earnest.
When the plate has been exposed, it is returned to the dark, where the still-invisible image is brought forth. Developer is poured across its surface, and within a few moments a negative appears. The warmer the day, the more rapidly the image emerges. Development is arrested by washing the plate with water. Prolonged development renders the blacks grey; insufficient development leaves the image too dense. I prefer a slight over-exposure followed by under-development.
At this point I depart from the practice of 1851: I do not employ cyanide as a fixing agent. I make use instead of a milder preparation of ammonium thiosulfate, one that will not prove fatal unless a man should drown in a vessel of it. The fixer removes the unexposed silver salts, leaving behind the metallic silver that constitutes the image. What remains is, in strict terms, still a negative—yet, resting upon a black ground, it appears as a positive.
The plate is then placed in a water bath for no less than half an hour—cyanide would have shortened this interval, but ammonium thiosulfate requires a longer period of washing. Thereafter the plate is dried and coated with a varnish prepared from the resin of the African sandarac tree, dissolved in alcohol and scented with oil of lavender. It is this final treatment that enables a tintype to endure for centuries.
A portion of the power of the tintype lies in its absolute uniqueness, and a portion in the inevitable chemical marks that arise from the imperfect handmade process. Each plate is singular and cannot be duplicated.
A SINGULAR COLLABORATION
As an artist I regard the making of a portrait as a collaborative undertaking. It is a rare opportunity for two persons to join in the creation of one remarkable work. It is not that I take a portrait of you, but rather that we make a portrait together. I desire to hear your thoughts, your notions, and your expectations, should you have any… and should you have none, that is well enough. I am content to conduct you through the process.
I consider portraiture a collaboration. It is a chance for two individuals to come together and produce one remarkable thing. I am not taking your portrait—I am making it with you. Communicate what you have in mind, if anything. If you have nothing particular in view, that too is acceptable. I shall guide you through the work.
—Patrick Cavan Brown