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.
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
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.
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.
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