Thinking of the possibilities of technology, I discovered that three factors determine the visual effect of a photographic image: the state of the object photographed, the condition of light and the length of exposure. The latter two are equivalent to aperture and shutter, the primary means of taking photos. Among the three, the most basic is light.When there is no light, no matter how fantastic the object, there will be no image. The specificity of light determines the image of a photographed object. The function of light is to shape and model. Speed directly determines the effectiveness of light. Thus, I derive my definition of photography—its essence is light and time.At a specific moment, light encounters the object to be photographed, and this is a “jiyu” (opportunity) for the object in the environment of changing light. “Ji” (occasion or chance) is representative of time for the object. Thus, I naturally decide to make light itself into an object. Using light, I directly create an object instead of merely revealing a shape. It requires a certain length of time for light to form and to present a shape. I start to think of the first aspect, which is the state of the object to be photographed and to ask myself, “What object can I create with light?” By now, you probably understand why I photographed the series of words written with light.Light sources are ubiquitous in photographs. For example, they are sometimes shown as lamps or the moon. However, these light sources are static. Once they move, they interfere with the presentation of other objects in photographs. When a light source moves, it creates a path. Photographs of urban car lights have almost become an independent genre. However, when the trace of a moving light source is abstract, its “chance value” is not very high. Only when the trace starts to form a specific shape dependent on chance can it become a desirable (and attainable) moment worthy of preservation.Words are a particular combination of abstract lines. When traces of light are combined to form words, the value of chance is magnified to the maximum. Words have advantages over images because they require a sequential reading. We start at the beginning of a brush movement and stop at its end. The sequence of words directs our gaze, and the traces of light develop in time. Only in this way can the image of a bull painted by Picasso by using a flashlight be transcended. As a time-based medium, this is the advantage of calligraphy over painting. When reading a line of words, we follow the brush movement from the beginning to the end and travel in time in an unchanging direction. Within space, only a temporally moving light dot is visible. Only when time is fixed onto a photographic surface can the continuous, temporal dot form words. These words are in fact invisible in space, except in a photograph. Only then is photography a necessary medium. This photography is based on the understanding of the essence of photography, but it also alters it.The essence of photography is light and time. This series of works can be said to be the natural result of the many years in which I contemplated this matter.On LightMy interest always lies between photography and calligraphy. How to have them interact is a big question.In the famous contemporary martial art novel Heaven Sword and Dragon Sabre written by Jin Yong, two martial art masters, Zhang Sanfeng and Zhang Cuishan, write calligraphy in the air, which later becomes a set of martial art movements. However, what influenced me the most is the story of Chan monks painting plum blossoms in the air. Some monks spent their whole lives painting plum blossoms in the air, but did not leave a single brush mark on a piece of paper.Chinese values can be summarized in the following manner: as subtle beauties, such as the footsteps of geese left on the snow, half hidden by floating light and passing shadows. What illuminates us is light that manifests in time.Photography is an event, or events continuously taking place in time. Light leaves traces in time; the brush leaves traces on paper. A line is drawn, a person passes by, a period of time elapses and an event takes place.A photographic negative is light sensitive. All forms on a negative are bestowed upon by light. In most photographs, light is invisible. It only outlines and highlights the forms of objects, but it, itself, is spread in the air. Light plays a supporting role, and objects the leading role. When we take photographs, we think that the negative documents the subjects, but in fact it documents light. I think perhaps I can give the leading role to light. With enough time and space, a conglomeration of light will result in movements like those of a brush.A negative is light sensitive, just as rice paper is to ink. Each movement of light—fast and slow movements, stops and turns—will leave a faithful record. When lighting is good and time is long, I will also leave traces behind when moving the light brush. This calligraphy is completed during the passage of time, just like the ink marks on rice paper, which are also completed over a period of time. It waits to be deciphered by the passing of time. Just like ink marks, traces left by light cannot be changed, perhaps even less than ink. The process of writing is an assembling and awakening of an individual, of time and of space. A person passes by a place at a particular time—this is fate. It creates meaning.On TimeWhen the shutter opens for a long time, light has enough time to travel through a certain space and to name the place. Then, traces of a light dot can become a word, a sentence or an inscription. A person passes by a place, emotion rises in his heart and he writes inscriptions to express it.For ancient Indians, the smallest unit of time is the “chana” (“ksana” in Sanskrit). I made a calculation based on Record of Travel in the Western Region During the Great Tang, written by the famous monk Xuanzang (602 - 664), and concluded that one second in our modern life consists of more than 300 “chanas.” That is to say that, when a camera light flashes (one 60th of a second), five “chanas” have passed.We always mistakenly think of photography as an instantaneous art form, but we forget that, within the period when a shutter opens and closes, what happens is an event, a drama, a history and perhaps even a miracle.The duration of time is flexible—it depends on our feelings. Thousands of years can be a blink, and one thought can span 3000 years.Time is meaningful because of our presence. Because of us, time becomes opportunity.Because of our presence, we realize that we should seize opportunities because they do not appear twice. We need to make decisions promptly, and according to different situations. On Place: Inscription and GraffitiIn a certain way, I think that these photographic activities are similar to the inscriptions written by literati. When they visited a place, they often felt an impulse to write something down—a word or sentence flowed naturally from their brushes.Meanings of words and sentences change because they have interesting relations with different locations. Sometimes they respond to them, just like characters accompanying images that illustrate their meanings. Sometimes they have absolutely no relationship with the location, but are nonetheless poetic. Sometimes they are recollections, and other times they are prophecies. Such writing is always temporally meaningful, perhaps because its medium is light.Using light to write needs proper handling of time and space. Time determines whether the traces will be visible and space determines the shape of words. Perhaps because of this combination of time and space, writing movements become heavy. I even have the feeling of “energy penetrating to the back of the paper,” something that is normally associated with writing Chinese calligraphy.From time to time I had to use my left hand to block the light of the flashlight in order to create breaks between strokes. I had to coordinate the movements of both hands. I had years of training in writing calligraphy, so naturally when using a flashlight to write, the strokes also have hooks and turns, fast and slow movements. In order to spread words in space, my feet moved as well. Because a camera can only produce a mirror image, I had to concentrate in order to write words in reverse. I was always soaked with sweat after completing a photograph. Some people commented that my movements in light writing are like practicing Taichi. Indeed. Finally, I discovered a way to make contemporary art while at the same time prolonging my life just like the goals of the practice in many traditional arts.I only thought of “graffiti” after finishing shooting at the Weiming Lake of Beijing University. I walked out of the North Gate and saw some graffiti on the walls enclosing a construction site. Movement of light only leaves traces on charge-coupled device (CCD). In a way it is a kind of graffiti that does not interfere with the urban environment!To write down one’s feelings at a specific site is a practice enjoyed by traditional literati. In fact aren’t the inscriptions of literati also a kind of graffiti? Inscriptions document emotions evoked by traveling (youxing). They are also an excuse to leave “goose’s footprints” on snow.Inscribers are people who are shaped and transformed by these sites. These people at the same time shape the sites. This is a re-defining of place in both directions. When a good poem is written by literati on a rock, the surrounding lakes and mountains are transformed. When a not-so-good poem is inscribed, it may just be a souvenir. Ink marks of later visitors will soon cover them and erase those left by generations and generations of passers-by. Because of the existence of the Red Cliff, there is Su Shi (1037-1101). Because of Su Shi, there is the West Lake.In different places, the transformation of writing in light is happening.The essence of photography is light and time. The essence of a human being is emotion and transformation—an “occasional” form of travel writing.