Now that we have our image safely cropped by virtue of having straightened it, corrected its perspective, and trimming for story impact and content, we can move on to the second C in the three Cs: Contrast.
Contrast is the process by which we adjust the overall exposure of an image and its internal relationships to the lights, darks and mid-tones. There are some who advocate that color adjustments should be performed at this stage but I am adamantly against it. I often find that color casts are not readily apparent in images or remain hidden until exposure, white and black points, and mid-tones are adjusted. I would rather adjust the contrast and discover a color issue than adjust color, then adjust contrast and then have to adjust color again. There are too many things that can go wrong in adjusting color twice.
Evaluating the image, much like was done in the series on crop, is the first thing you should do. At a glance does the image look dark? Does it look light? If it does, does the darkness or lightness detract or add to the story (or drama) of the image?
Getting the exposure right in the camera is always preferable so that the overall brightness of an image doesn’t have to be modified. As is often the case in the real world, the camera, the scene, and your technique will contrive to give you a perfect exposure. Sometimes this happens-sometimes it is elusive. Other times, a perfect exposure does not tell the story you wish to tell and an exposure adjustment will aid you in telling your story.
When I look at a photo, I ask myself: “Is there anything white in this scene and is it white in the image I have captured?” Nature contains white in clouds, snow, bright lights, and other instances. It is not a photographic sin to portray that there are whites in an image. If the whites are not white, or things that aren’t white are white, exposure needs to be modified to reflect this. This can mean brightening a dark image or lightening an image.
Common Coarse Adjustment Exposure Controls
Software can accomplish this through a variety of means. Histogram adjustments are common tools. Every software package for image editing has them. RAW converters typically call this an exposure slider which can pull an image up and down by several stops. Image editors call them different names and include coarse tools such as Brightness/Contrast. Medium grade tools such as Contrast Enhancement, Level Adjustments, Histogram Adjustments, are three of the names from Corel PhotoPaint, Adobe Photoshop and Corel Paint Shop Pro Photo. Finely tuned tools such as Curves, Tone Curves, targeted adjustments, lenses and other items can get dialed into proper contrast. The bottom line is that even though software differs, you can achieve similar adjustments if you can ID the tool you need.
Various Software’s Contrast Adjustment Tools showing similarities for adjustment of the the Histogram.
Move the image’s exposure until the image looks right to you. When you are satisfied with the overall brightness of an image, you can begin to work on the other items.
“Wait, Rikk,” you say. “I am still a little fuzzy on this whole histogram thing. Can you explain that?”
I can-but that will wait for the next installment.
Rikk Flohr © 2007