Friday, November 30, 2012

The Groundglass

Composing a photographic image is really the "guts" of the photographic arts.  A little while back here I delved into many of the details involved in the decisions that must be made in order to arrive at a particular composition. Those particular decisions I examined were independent from any hardware considerations. All of these "editing" choices were influenced solely by the mind and artistic sensibilities of the artist. I'd like to turn now to the various hardware (and their related techniques) that enable the photographer to make those choices and effectively arrive at a successful composition.

How does a photographer know and select when the right image has been achieved? Three basic methods (and their respective hardware systems) have been developed over the past couple of centuries: the groundglass, the optical viewfinder, and P&S (point and shoot). Although this list is more or less an historical sequence it does not quite reflect a linear evolution as it has ebbed and flowed and produced hybrid results along the way.

Rudimentary groundglass setup,
using a magnifying glass as the imaging lens,
 and white plastic film as the groundglass,
© Bill Brockmeier, 2012
Early in the development of photography the photosensitive material responsible for the recording of the image was in the form of a plate. In the beginning it was the metal plate (daguerreotypes, tintypes, etc.), which eventually gave way to the glass plate. Since these rigid and planar photosensitive surfaces were modular in form it was pretty obvious early on that they could be simply exchanged for a similar-sized glass plate that was "ground" rough on one side (frosted). This frosted surface would diffusely scatter the image's light, and would act as a kind of projection screen so the image itself could be viewed and focused properly. This would also allow the photographer to adjust the location and direction of the camera while watching the image in real time.

Fundamentally, the operator was looking directly at what the final photograph would look like, identical in size as well as composition, albeit upside-down due to the geometric realities of lenses. When in place, the groundglass became the surrogate for the photographic plate. Once the proper focus and desired composition was set the groundglass could be removed and the actual photographic plate inserted in its place. Finally, the image would be exposed onto the photographic plate and recorded for posterity. With the camera work complete all that remained was to chemically reveal (develop and stabilize) the image on the plate.

HIS OWN WORLD, © Bill Brockmeier, 2012
all rights reserved.
This ability to directly see what the final photograph would be seemed axiomatic for the definition of photographic art. Analogous to a painter viewing a scene and then manipulating pigments on a canvas, the photographer would view the scene directly and then retire to beneath his blackout cloth to view the image on the groundglass and manipulate it by modifying the location and direction of the camera and its lens settings.

Hidden beneath his black cloth and behind his camera, the artist is optically isolated from the real scene and is alone with his illuminated image on the groundglass. Of the three basic composition systems I mentioned above this method probably most removes the artist from the external reality which is the source of his image. This situation, coupled with the fact that the image is being viewed upside-down, provides a certain level of abstraction of the image. Only by frequent immersion in this inverted image-world and by a dogged determination to see the real world-as-it-is beyond this inversion can the abstraction be avoided.

The image on the groundglass is actually evidence not of the scene (the objective reality) but rather of the photograph– the image, the art, even the mind of the artist (the subjective reality). This groundglass method of composing the image, as archaic and outmoded as it seems today, has achieved a high renaissance in recent years. Although most don't realize it, modern computerized digital cameras possess their own high-technology version of the groundglass– the electronic display.

The electronic display–
a modern version of the groundglass plate,
© Bill Brockmeier, 2012
This electronic display sits on the back of the camera, just like the real groundglass of more than a century ago, and is the ultimate result of an image focused on the photosensitive surface inside the camera. While the true groundglass reveals the image simply and directly, the electronic display is coupled to the image by a hidden and unimaginably complex chain of digital electronics. The photographer here, as with the groundglass, is looking at a surrogate of what the final photograph will actually be, rather than somehow looking out directly into the scene itself. One difference, however, is that modern camera makers have bowed to conventional notions of reality and have re-inverted (or maybe un-inverted) the image so the photographer views it right-side-up. Although most users probably appreciate this I'm not sure this is actually a plus for the artist. I believe that leaving the image upside-down can allow a more intimate access to the actual power and subtlety residing in the composition of the image.

Also, because the photographer is looking at an image that is within arm's reach (for both the groundglass and the electronic display) he is further separated from the external world. The fact that this image is physically close to the photographer causes his eyes to accommodate, or focus closer, on this nearby object. That may not seem like much of a consideration, but the brain interprets what it sees substantially based on this level of accommodation. Certain powerful optical illusions (like the "moon illusion") depend heavily upon the degree to which the eye's lens is focused. Looking at an absolutely identical image at close range is perceptually very different than seeing the original scene at a distance. This effect can further abstract the image for the photographer.

These abstracting aspects of the electronic display– the new "groundglass"– have revolutionized my own approach to this art. Once I became connected to the immediate ability to hold in my own hands a replica of the final photograph– before it had even been taken– I couldn't imagine ever going back to the "dark ages" of shoot-and-hope.

No comments:

Recent Posts