A comparison between the way film-based cameras and digital cameras capture spectral information and transpose that information into black and white images.
Photography is all about Light. The more we understand about the way light behaves, the better we will understand how to capture it, edit it, and render it in both display and printed form. In this session we’ll look into the light-capturing capabilities of light sensors of two types: CCD and CMOS. I won’t get into the technical differences between the two technologies because it is not germane to this discussion.
What these two systems do have in common is the challenge of recording and interpreting spectral data (the color properties of light) and rendering that information in monochromatic form. While they both see the same light, they record it quite differently. All serious photographers love black and white photography. And all serious photographers recognize the difference between film and digital black and white images. What is not immediately obvious is why there is a difference. I’ll try to shed a bit more light on this issue in this second session in the series.
Film cameras make use of the light-response attributes of silver-halide, and various black and white films are composed of slightly differing formulations of silver and bromoiodide atoms as well as other coatings that record nuances of colors that affect the black and white interpretation of color subjects.
Digital cameras work on a more sophisticated system that involves electrical current. Photo cells actually count photons (the atomic level of light measurement), and use electrical current to amplify the levels (based on the ISO settings).
But here’s where the personality of monochromatic digital captures literally falls flat. When a digital image is captured in monochrome form, the camera discards all RGB information and only records luminous data. While this sounds reasonable for a black and white result, it negates the nuances of spectrally-weighted transformation. Each manufacturer determines how each color in light is parsed as a monochromatic value.
You are literally at the mercy of the engineers writing the algorithms. A process that can be quite mathematical and romantically sterile; all information is recorded in a very flat and mechanical manner. While some very interesting and useful translations are offered by come camera manufacturers, you are still locked into someone else’s interpretation.
When digital images are captured in full RGB color and then transposed into black and white during the image editing process, you, the photographer get to creatively transpose those spectral colors into gray tones that can more richly interpret colors to tones.
If you are editing in Adobe Photoshop, open the Black and White… menu item from the Image/Adjustments menu. Within this very powerful interpreter, each color can be tuned to a specific gray range, giving you to the total control over how each color is transposed into the monochromatic mode.
The Preset menu offers a number of springboard settings that can be modified to your own liking. The little gear symbol to the right of the Preset menu allows you to save and recall any number of color/mono transpositions. This puts you in control of the conversion process and gives you the power to shape your own black and white images.
That’s the way I sees it. Take some time to experiment with these tools. Shoot some images of diverse color themes and develop your own “signature” conversion style. Very powerful stuff.
Once again, the more you learn about the behavior of light, the better your photography will turn out. Get bright about light and the dividends will pay off big time.
I also suggest that you take the opportunity to learn more about the basics of light and color from my video series entitled the “Gotta Know Videos: Part One- Light and Color.” http://gottaknowvideos.com
Until next time, this is Herb Paynter