When I am asked to teach people how to approach image editing-for whatever purpose, I take them to the pneumonic that I hold as mantra. “Start with the three Cs.”
Before I get too far in this article, I should tell you what the three Cs are.
Crop • Contrast • Color
I always start with these three concepts (another C) whenever I begin evaluating an image from a digital camera or a scanner. The order is deliberate and some gurus council adjusting one or the other of these before another. This is what works for me so I stick with it, teach it, shout it from the mountaintops.
Crop, to me is the natural place to begin. I want to work on the part of the image that tells the story. This usually means cutting off pieces of the image to make the focus stronger or to remove extraneous, even distracting, material. That is why I always straighten an image first. Woah! You say. Straighten? I thought you said Crop! I did. There’s no mistake here.
Look at this image of Devil’s Tower. By straightening the image, the gray corners appear marking images from the original footprint of the image where no pixels now exist. Not only that, the angles of the rotated image now require a crop tighter than the original image as noted by the red line. Thus, without applying a crop, the image is smaller than it was. It would be terribly disappointing to crop this image for content and then realizing as you straighten the image that you don’t have enough pixels to finance your crop.
The same is true of perspective corrections. When you do a perspective correction you create the same gray triangular regions but they are not symmetrical like straightening voids. Perspective correction by leaning a picture in or out-either top-to-bottom or left-to-right, further reduces the number of pixels you have to work with. That is why it is imperative to have the image capture as close to level as possible and if practical, in the field of perspective you desire. No sense in wasting a large percentage of those precious mega-pixels.
The reason I crop first is to, first of all zero in on my subject and enhance its drama in the frame. Second, cropping often eliminates issues in contrast and color. Brightest parts of the image tend to be at the top and darkest at bottom. Distractions tend to the left or right. By cropping those portions out you may save yourself the trouble having to adjust them latter. You never want to adjust the exposure or color of an image to fix a problem area only to crop that problem area out later. (Actually you should never adjust an entire image to correct an isolated problem but we will cover that in another article later)
Now that we have our image straightened and perspective corrected we can get with the business of doing the actual crop. Sometimes the end format of the image will dictate the crop but the better, more aesthetic, way to tackle the image is to let the story of the picture dictate the crop. We will pick up these choices next time.
Rikk Flohr © 2007