Blacker than Black
Berlin-based lithographer and printer Dieter Kirchner is causing
quite a sensation with his invention of 'Skia Photography'. This
photo printing technique makes details visible that remained
imperceptible in conventional reproductions. In an interview,
Kirchner tells us how it works.
Dieter Kirchner, a man in his mid-sixties with snow-white hair and a full beard, leans over the printed photograph. Using a spectrophotometer, he measures the intensity of the black on the freshly printed sheet at the Heidelberg Print Media Center in Wiesloch. "A density of almost 2.7. We can make it a little blacker still", he murmurs. Kirchner is a master of photo printing. For years, he has been working on a printing technique that can expand the color spaces, so they come as close as possible to the spectrum of colors that can be perceived by the human brain. The measurement of 3.0 is absolute blackness and corresponds with the maximum contrast range perceptible to the human eye. We start seeing black at a density value of 2.2.
Dieter Kirchner, a man in his mid-sixties with snow-white hair and a full beard, leans over the printed photograph. Using a spectrophotometer, he measures the intensity of the black on the freshly printed sheet at the Heidelberg Print Media Center in Wiesloch. "A density of almost 2.7. We can make it a little blacker still", he murmurs. Kirchner is a master of photo printing. For years, he has been working on a printing technique that can expand the color spaces, so they come as close as possible to the spectrum of colors that can be perceived by the human brain. The measurement of 3.0 is absolute blackness and corresponds with the maximum contrast range perceptible to the human eye. We start seeing black at a density value of 2.2.
Mr. Kirchner, have you reached the limits of the human brain's
ability to perceive images with Skia Photography?
Kirchner: Yes. Skia prints are the kind of photographic images I have dreamt of all my life. Traditional manual prints have a very limited visual image gamut. Roughly one third remains invisible. Skia Photography achieves an image gamut that touches the boundaries of vision. Our brain perceives an image gamut of approximately 3.0 optical density. Depending on the negative, Skia prints can reach an optical density ranging between 2.8 and 3.0. For the first time, that enables us to transmit all details captured by the camera onto the print. Never before have there been photo prints with such shadow details and such a large tone range.
Previously invisible details such as fine individual beard hairs suddenly become visible. How do you do that?
Kirchner: Three-dimensional vision depends on simultaneous contrast and image contrast and thus on the intensity of the optical density. The greater the optical image density, the better our three-dimensional vision. Very fine details such as hairs disappear in the surrounding density of a non three-dimensional image. The three-dimensionality of a Skia image brings them to bear and makes them discernible to the viewer.
Kirchner: Yes. Skia prints are the kind of photographic images I have dreamt of all my life. Traditional manual prints have a very limited visual image gamut. Roughly one third remains invisible. Skia Photography achieves an image gamut that touches the boundaries of vision. Our brain perceives an image gamut of approximately 3.0 optical density. Depending on the negative, Skia prints can reach an optical density ranging between 2.8 and 3.0. For the first time, that enables us to transmit all details captured by the camera onto the print. Never before have there been photo prints with such shadow details and such a large tone range.
Previously invisible details such as fine individual beard hairs suddenly become visible. How do you do that?
Kirchner: Three-dimensional vision depends on simultaneous contrast and image contrast and thus on the intensity of the optical density. The greater the optical image density, the better our three-dimensional vision. Very fine details such as hairs disappear in the surrounding density of a non three-dimensional image. The three-dimensionality of a Skia image brings them to bear and makes them discernible to the viewer.
What is the technology behind Skia Photography?
Kirchner: The negatives, slides, or raw data are captured in two different digital data records. An electronic darkroom computes the gamma curve needed for the development of the printing process. That results in up to five data records. Two of them form the shadowgraph in the printing press, and two others determine the tone range. The developer substances hydroquinone and Metol are assigned to them according to color. That lets me individually select the image gamut, shadow details, tone range, and saturation in the press according to the f-stops. That, of course, requires the tones to be transmitted in the press with much accuracy. A few years ago, I developed a new standardization method for that purpose. It turns the press into a film processor.
Why have you chosen to print on Heidelberg presses?
Kirchner: Because of their technical design features. With their consistent water distribution in the printing direction, Heidelberg presses are cut out for this technique. That makes a tonal value difference with a precision of 0 to 1 % possible. Along with the PAN4C standardization, that lets me control the printing process with the greatest precision. For instance, I can open or close the aperture by half an f-stop in the shadow areas, or I can change the middle tones by modifying the aperture setting. That requires a very short press reaction time.
The first book with original Skia Photography prints has already been published by Moser Verlag in Munich. How did that come about?
Kirchner: The first book is by Ulrich Mack. It deals with the Ruhr and contains photographs from 1959. It is modeled on 19th century photo books into which original photographs like albumen photographs or calotypes were glued. With Skia Photography, photo books in small editions that show the viewer the original photos are being published again. Next to the general flood of coffee table books, those special books that allow a new dialogue between the viewer and the image are back again.
Kirchner: The negatives, slides, or raw data are captured in two different digital data records. An electronic darkroom computes the gamma curve needed for the development of the printing process. That results in up to five data records. Two of them form the shadowgraph in the printing press, and two others determine the tone range. The developer substances hydroquinone and Metol are assigned to them according to color. That lets me individually select the image gamut, shadow details, tone range, and saturation in the press according to the f-stops. That, of course, requires the tones to be transmitted in the press with much accuracy. A few years ago, I developed a new standardization method for that purpose. It turns the press into a film processor.
Why have you chosen to print on Heidelberg presses?
Kirchner: Because of their technical design features. With their consistent water distribution in the printing direction, Heidelberg presses are cut out for this technique. That makes a tonal value difference with a precision of 0 to 1 % possible. Along with the PAN4C standardization, that lets me control the printing process with the greatest precision. For instance, I can open or close the aperture by half an f-stop in the shadow areas, or I can change the middle tones by modifying the aperture setting. That requires a very short press reaction time.
The first book with original Skia Photography prints has already been published by Moser Verlag in Munich. How did that come about?
Kirchner: The first book is by Ulrich Mack. It deals with the Ruhr and contains photographs from 1959. It is modeled on 19th century photo books into which original photographs like albumen photographs or calotypes were glued. With Skia Photography, photo books in small editions that show the viewer the original photos are being published again. Next to the general flood of coffee table books, those special books that allow a new dialogue between the viewer and the image are back again.
How can the development of Skia Photography influence offset
printing, and what will offset printing be like in the future?
Kirchner: Skia Photography goes to show that offset printing is not limited to low-cost mass prints, but can also produce most excellent images in a quality hitherto unknown. That is the basis for the printing quality of the future. I believe the development principles of Skia Photography will soon be integrated into offset printing technology, so offset printing will remain the most important and creative type of printing in the future.
Kirchner: Skia Photography goes to show that offset printing is not limited to low-cost mass prints, but can also produce most excellent images in a quality hitherto unknown. That is the basis for the printing quality of the future. I believe the development principles of Skia Photography will soon be integrated into offset printing technology, so offset printing will remain the most important and creative type of printing in the future.
Skia is Greek for 'shade'. 'Skiagraphy', shadow writing, is how the British photographic pioneer William Henry Fox Talbot called the negative-positive technique he developed in 1835. It enabled the reproduction of a photograph by making positive prints from a negative.
