Plugged In: Balanced exposure, contrast not a gray area

By Joseph Kashi, for the Redoubt Reporter

Last week, we discussed why the Zone System is the classic approach to making exhibition-grade photographic prints and why its use with film required a degree of technical knowledge and personal discipline that generally confined its use to very serious photographers.

Digital technology has changed all that, not only for traditional, black-and-white photography, but also for color photography. As a result of the high degree of control recently possible with digital color images, color photography is finally gaining respectability as fine-art photography.

The procedures I suggest are applicable to almost any digital image, but I suspect that readers who are more serious about photography will be using compact cameras or larger, digital SLR cameras that can record data as inherently more-controllable, RAW-image formats.

Taking the picture

Major, visually obvious tonal transitions, such as from middle gray to light gray, are considered to be a one-zone change.

Each zone increase is equivalent to doubling the amount of light that strikes the sensor or film. This in turn is equal to opening the lens by a full traditional “f stop,” such as changing from f4 to f5.6 or from f5.6 to f8. It’s also equal to doubling the exposure time. Another term for the same degree of exposure and exposure correction is one “exposure value,” usually shortened to 1 EV. Modern digital cameras usually use the EV terminology. Decreasing exposure works in the same way, but in reverse.

An ordinary photographic scene usually averages out to Zone 5, which is a middle gray. Caucasian skin averages to a lighter grey, a Zone 6. Shadow areas with strong and evident detail works out to a Zone 3 or so, while bright areas that retain good texture usually fall in about Zone 7. Zone 2 would represent deep shadows while Zone 8 would represent highlights with some barely perceptible detail.

Nonaverage lighting situations, such as backlit subjects, require one to two zones difference to avoid overexposure or underexposure. For example, if you base your exposure upon metering Caucasian skin and use that basic exposure determined by your camera, then the image will be underexposed by one zone, because it received about only half the needed exposure. That’s because Caucasian skin really is a Zone 6 light gray, but your camera tries to average everything to a Zone 5 medium gray. That’s exactly what it will do unless you, as a knowledgeable photographer, personally adjust the exposure and increase it by one zone (1 EV value, 1 f stop).

Obviously, controlling overall image contrast is important to make visually exciting images. This can be done most effectively with a calibrated computer and printer after you’ve taken your photos. If you are willing to devote a little time later to correct your images with a computer, then setting the camera’s contrast range to “low contrast” and “low saturation” will give you more leeway to later work with shadows and highlights, but you’ll definitely want to computer-correct such images so they’re appealing.

Most people find a low-contrast image to appear flat and not very interesting. Usually, the average consumer prefers the appearance of a medium-high contrast image. But be careful. Too much contrast looks artificial and harsh. Harsh tonal transitions are sometimes useful to achieve special effects, but look out of place in most photos.

If you want more “pop” right out of your camera, then set the contrast control to higher contrast and the saturation control to higher, more vivid saturation.

However, if you’re just taking a few casual snapshots in JPEG, then by all means leave your camera set to its default “normal contrast” and “normal saturation” settings and use the images straight out of your camera.

Digital processing

I’ve found that the following digital processing procedures best approximate traditional Zone System controls for me.

In Adobe Lightroom and in Photoshop Adobe Camera Raw, several adjustment sliders fine-tune specific tones in addition to overall exposure and contrast adjustments, but be careful not to overdo their use or your photos will appear to be overly manipulated, rather than natural.

The “blacks” slider controls the blacks and the near black tones to achieve a feeling of depth and robust substance in a print.

The “fill light” slider brightens dark gray tones and makes their detail more apparent, just like the old adage to expose for the shadows.

The “brightness” slider moves the bulk of tones brighter or darker without greatly affecting near blacks and near whites and basically acts like a specialized contrast control.

The “highlight recovery” slider reduces the brightness of highlights without greatly affecting middle and dark tones, mimicing the effect of the Zone System’s variable development.

The “clarity” slider in Lightroom is not sufficiently appreciated. It enhances the microcontrast between small individual details in an image. This has several effects, the most noticeable of which is that, unlike “sharpening,” increasing the “clarity” control can make an image look much sharper without increasing apparent noise and graininess.

Using the “clarity” control also tends to make an image appear to be more contrasty without actually increasing overall contrast to an unpleasant point. I had the opportunity to speak with Lightroom’s project manager, himself an avid photographer, and he told me that the clarity slider was usually the first adjustment he made. Using the clarity slider is comparable to using an edge-enhancing acutance type film developer in the old days.

If you decide to work with digital black-and-white images, then by varying the saturation and brightness of eight separate color channels in the “HSL” panel, you can not only mimic, but in fact exceed the monochrome effects that a black-and-white Zone System photographer could achieve using strong filters, such as a blue, orange or red filter when exposing the photograph.

Another underappreciated but really interesting control in Adobe Lightroom is the “vibrance” slider, which has no Zone System equivalent. This is a modern concept that’s only achievable with digital photography and computer processing. Basically, the vibrance slider causes different colors to become more or less differentiated from each other in a subtle but useful way. Vibrance is somewhat like color saturation but more restrained and natural in appearance.

One other Adobe Lightroom software control has no Zone System equivalent — the “target adjustment” function that allows you to precisely control the saturation, brightness, tone and grayscale mix of a single color or element of a digital image. Point, click and roll your mouse wheel until you like how it looks.

Ultimately, your work will be judged by the quality of your final images. It’s just as important to learn how to make excellent prints as it is to first take a properly exposed, high-quality image.

Digital printing

Use a fine-art, inkjet printer that’s capable of accurate, high-quality color and gray tone reproduction, and then profile every printer in conjunction with your monitor so that final prints from your printer match what you’ve seen on your calibrated screen.

  • Among current, medium-format, photo-grade printers, the Canon Pixma 9000 Mark II, the Epson 1900 and the Epson 2880 printers are probably the best buys among printers that can print exhibition-quality prints up to 13-by-19 inches. The Canon, about $450 from http://www.amazon.com, is the least expensive, and the newer model seems to more than hold its own against the competition.
  • The Epson Stylus Pro 3800, about $1,150 from http://www.newegg.com or http://www.amazon.com, is the least expensive and one of the best printers capable of larger, 17-by-22-inch prints. It has an excellent general reputation but will likely be superseded in the near future. There have been some recent reports that reliability has decreased.
  • The HP DesignJet 130nr is the least expensive, large-format printer that will print 24-by-36 or longer prints. This printer varies, depending on current HP sales, between $1,500 and $1,900, including the roll feed, paper cutter and printer stand options. I much prefer using HP’s Premium Plus Photo Satin paper with this printer.

Any of these printers are capable of high-quality, generally lifelong results. Stubs Office Supply in Soldotna can order supplies for any of these printers for you.
Be sure that when you print any photographs, your photo software is set so that it uses the most recent monitor and printer calibration profile. Profiling your monitor and printer do no good if you don’t use the calibration data to correct and print your image. If you have more than one printer, then each printer-monitor combination must be separately profiled and your software set to use whichever profile matches the printer that you then intend to use.

I prefer to turn off the overhead fluorescent lights in my office when working with photographs. Even though these lamps are listed as “daylight” fluorescent bulbs, they still distort the image’s color on both the monitor and when viewing the final print. Fluorescents usually impart a greenish cast. Incandescent and halogen bulbs usually cause the image to look too yellow, while cloudy daylight makes an image look more bluish than it really is.

No real-life viewing conditions are perfect, but the most workable procedure for my own conditions is to make corrections on my monitor while the room is illuminated only by natural light through the windows, and to evaluate final prints under a combination of halogen desk lamp and natural window light. Remember that most photographic prints are illuminated with incandescent or halogen lights that have a yellowish color cast, so you may need to adjust your prints to look best under expected viewing conditions.

True in practice?

I’ll let readers be the judge of whether my comments in these articles prove true in practice.

Over the course of the next few weeks, I’ll be opening two separate, themed photo exhibits, mostly consisting of images not previously exhibited. One show, exhibiting at the Homer campus of Kenai Peninsula College, will consist of a number of “Not Quite Black and White” digital color images that appear to be monochromatic at first glance but that are, in fact, more subtle color images.

These are evident examples of applying Zone System concepts to modern digital photography. The opening reception is from 5 to 6:30 p.m. Aug. 5 at KPC’s Kachemak Bay Campus. Small, Web-resolution JPEG images of the prints in the Homer show can be viewed on the New Content page of my law office Web site, http://www.kashilaw.com.

The other exhibit is at the Kenai Fine Arts Center in Old Town Kenai, with an opening reception starting at 6 p.m. Aug. 6. Some of the prints first exhibited in the Kenai show will share the “Not Quite Black and White” theme with my concurrent Homer show. However, the Kenai show will be about twice as large, with many color prints that find what I hope are interesting apparently abstracted images directly in real life — “Abstractions from Reality,” if you will.

You’re invited to both exhibits and their receptions, and I’d like to hear your candid opinions.

Local attorney Joe Kashi received his bachelor’s and master’s degrees from MIT and his law degree from Georgetown University. He has published many articles about computer technology, law practice and digital photography in national media since 1990. Many of his technology and photography articles can be accessed through his Web site, http://www.kashilaw.com.

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1 Comment

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One response to “Plugged In: Balanced exposure, contrast not a gray area

  1. Pingback: Plugged In: Digital imaging shifts photography’s paradigm | The Mouth of The Kenai

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