kurt

Negative Density

I've been researching the Basic Daylight Exposure system (or Sunny 16) in an attempt to take control of the creative exposure choices that reliance on a metering system severely limit.

It occured to me that the idea of "correct," "proper," or "normal" exposure is dangerous to the photographer. Implicit in the idea of normal exposure is two incorrect assumptions: 1- that there is a binary nature to capturing light on a negative, one that is either the right or the wrong exposure. 2- that the image captured on the negative is exactly what gets printed.

The first one is wrong because the photochemical emulsion is an analog medium (don't get hung up on a comparison to "digital" imaging, which is not actually "photography" at all, because the principle applies in the same way). There are infinite ranges of exposures that are acceptable for the creative purposes of the photographer. The main concern is achieving an acceptable negative density during the exposure. Remember the equation: exposure = intensity x time. Intensity is "brightness" controlled by the light source and the aperture. Time is controlled by the shutter speed.

The second arises from the popular use of the phrase "take a picture." The phrase condenses a multi-step process in which there are a great many intermediaries. Exposing the negative, processing the negative and creating a print from a negative are all distinctly separate phases of “taking a picture” that allow for a large possibility space of creative choices. Consumer photography typically limits the creative input of the photographer to the initial exposure. The lab, an automated machine in most cases, takes care of the processing and printing according to a set of “standards” determined by the concept of “normal exposure.” What happens in the creation of the image after the shutter release is just as important as the framing that the photographer selects. But the "black box" system of processing causes pictures often to come back from the lab looking different than you expected when you shot them. If you try to shoot a silhouette for instance, the lab will try to lighten the image by several stops (increasing the appearance of grain) in an attempt to gain definition in the face of the subject. Kodak processing will actually put a sticker on the photograph explaining what is “wrong” with the image and how to “fix” it in the future.

Control of the aperture and the shutter is how the photographer selects what parts of the image the film should be sensitive to. So the metering system in your camera also makes a great number of assumptions about what you want. And in a consumer market this is considered advantageous, an “advanced” metering system adds to the feature set.

But I want to take control of the image. By relying on the reflected light meter in my camera I am relinquishing artistic control and knowledge of what the negative will record. Using the Basic Daylight Exposure system I know exactly what part of the image I am exposing for. And if I know the exposure latitude of my film stock then I will have a pretty good idea of what the negative density will be. Ansel Adams called it the Zone System. Look it up on Google. It’s amazing.

Try to think about the implications that this has for digital imaging. The same pitfalls exist.

I believe that we should be aware of what artistic input we are sacrificing. Especially in our new medium of interactivity.