Teaching digital photography has been at times, difficult. Perhaps the biggest impediment to success is the lack of terminology that would bridge the differences between traditional and digital photography. I believe I’ve found a way to use the Zone System we’re familiar with (don’t give up right away if you don’t consider yourself an expert) to take the mystery out of digital and speed the learning of the new technology.
It is my belief that any digital product you choose should be able to be able to make images at the highest level it’s capable of with a minimum of stress and as short a learning curve as possible.
Consider if you will, the last film camera you purchased. If you are a professional photographer, it probably was not your first camera. Your last camera purchase probably required learning the camera controls and perhaps a few new film emulsions. Chances are, you got excellent results almost immediately. This is not the standard digital experience. Why?
If we consider the numerology of digital photography we usually end up with a system with 256 tones or gray levels. I wonder if the digital folks who developed and instituted this system could come up with a progression even more obscure. Actually, computers count very effectively in multiples of 2 which when factored, becomes, 4, 8, 16, 32, 64, 128, 256, 512, etc. If you’ve been around computers any length of time, these numbers are familiar as bus speeds, ram caches and ram chipsets. The 256 gray levels system divides the gray scale into 256 sections with black at 0 and white at 255. Why do I consider the 256 scale troublesome? What value in a 256 scale would you suppose is an appropriate value for Caucasian skin tone in open shade? If you don’t know you are not alone.
I believe the understanding of 10 different tones is far more approachable than 256. Most photographers have heard of Ansel Adams and his Zone System. Ansel’s photographs have moved all viewers with their impeccable transition of tone. His ability to predict his final image with all its splendor was based on understanding his equipment’s “Show Info” (Ansel used a 1 degree spotmeter), thereby enabling him to modify the exposure and development of his media, which resulted in producing exactly what he envisioned when he tripped the shutter.
It is my suspicion that photography needs a method of aligning digital capture with traditional implementation and the Zone System may very well be that link. The Zone System is easier to use within the digital workflow. The testing difficulties that drove most would-be practitioners away from the Zone System are nonexistent with the computer moving the densities. And while I do not recommend depending on the monitor for direct visual interpretation of your work, it is valuable for gauging the effects of changes by the photographer, especially when one can toggle “before” and “after” with an Edit>Undo command. One can implement a Plus 1 “development” for example and if it’s not perfect it can be undone and another, different development can be tried. You can see the effect and, if you like it, save it. In addition, that development can be applied in any fashion anywhere from highlight-to-shadow.
Where the 256 levels system is difficult is in the prediction of proper placement of reflectances. Many commercial photographers use Polaroid to “proof” their images before shooting film. While commercial photographers use Polaroid for the proofing of images, the fine art shooter has traditionally utilized the careful metering of scene contrast to make appropriate decisions on exposure and development. The counting of the number of stops in the scene contrast as compared to the number of stops the film will hold has allowed the careful shooter to fit (expand or compress) the scene on his film of choice. The digital process does not yet have a “Polaroid” for the proofing of images. Just like film based photography, the successful digital image must render the correct number of tones on the target. In addition, the transition of tone must communicate the emotional intent of the photographer or client. My biggest difficulty in teaching the digital process has been the communication of information that would allow verification of the photographer’s pre-visualized intent. My first efforts in 1992, with Sony’s Seps 1000 video capture were centered around the gray level scale, 0-255. The 256 level scale surfaced again in 1994 when I started shooting the Leaf DCB. In fact, almost all capture devices use the 256 level measurement standard.
In practice, the 256 level scale is geared to accurately placing images on a printing press. In reality, each level occupies less than one percentage of dot on press. Presses have ink limits that do not exceed 100% for any of its colors, which translates to 100 possible tonal differences. The most fabulous press in the world would be challenged to print 70 visually discernible tones, and I’d guess an average sheet fed press might print 50-60 discernible tones. Why should I be concerned with less than one-half dot % accuracy when I cannot have 2% dot accuracy on press? Even the most accurate output device in the printing industry, the imagesetter, is calibrated to a 1% error value. There is no ability to specify and receive any specific gray level on press; in fact the reflection densitometers used by the pressmen don’t have 0-255 readouts. The only place you’ll ever see the gray level measurement is on a monitor, which is usually not the target we’re concerned with.
In normal practice, the digital capture is made and the endpoints are adjusted (using software, or lighting, or both). The density range (the number of tones between highlight and shadow) is fine tuned with a Levels command and the transition of tone is remapped with a Curves function, usually applied in Photoshop. For most digital captures the proper exposure and transition of tone are implemented with a target made by Kodak called the Q-14. This target has 20 different shades of gray on it starting at white and incrementally gaining in density with the lowest reflectance becoming black. The lowest reflectance reads 19 which indicates a density range of 1.9D. Each reflectance is numbered and indicates the density range between it and the brightest patch on the gray scale. Usually aimpoints are indicated to the photographer; he must make sure that specific reflectances read nominal values specified by the separator or printing press. The photographer must then adjust a characteristic curve in a software program to make the reflectances read the specified values. Choosing the appropriate density and transition of tone from within the Curves dialog box traditionally relies on the monitor representation as a guarantor of predicting the outcome of the adjustment. Photoshop’s (and many other image editing packages) Show Info dialog box reports a “before” and “after” of any sampled point in the image. Most usual is the display of RGB (0-255), or CMYK (0-100%); whose subtractive color space and gray component make difficult the understanding of what density the sampled reflectance really is. If this described picture-making process does not remind you of photography, we’re in agreement. In actuality, this procedure is the application of a scanner interface and I think it has very limited relation to traditional photographic procedure.
As photographers, we know that making changes to the number of tones (and their transitions) after the capture has some drawbacks. Graded papers are largely misused (they’re often used for density range correction rather than the gamma correction they’re really designed for), flashing prints often veils highlights, and overextended developments commonly result in fogging the opposite end of the scale. How we might wish for the negative that makes the “straight print”! Digital is no different, but how do we know when we’ve done it right? We know we cannot trust the monitor, so we use the info report. The traditional 256 level information report makes our task all the more difficult because it’s not an intuitive progression.