When And How To Sharpen

March 26, 2007

Q) Most professionals recommend sharpening a digital image before printing.
I like a sharp image and use either a tripod or flash to improve the capture results. I feel using sharpening prior to printing makes the final print, in some cases, look unnatural. Why do the professionals use sharpening, and should I be using it?

G. Furford
Via the Internet

A) All images that come from a digital camera, regardless of the care with which they’re captured, are in need of some sharpening to make them match what the lens actually saw—this is due to the technology involved in digital photography. In some cases, if you’re shooting in JPEG format, the sharpening can take place in the camera’s internal processing software.

For most of us, there’s usually some additional sharpening to be done when we’re working on the computer within the image-processing software, especially if the capture is in RAW. There are a number of places within these programs where we can take the opportunity to sharpen the image. Sharpening can be done from within the RAW conversion software; there are also several different sharpening options in Photoshop. Lightroom offers the option within the image-editing process.

My preference is to sharpen an image within Photoshop, though many Photoshop pros prefer to sharpen at the end of the process (there can be a trade-off in sharpening artifacts). I want to know at the beginning of my work whether an image will meet my standards for sharpness. I do my sharpening using Smart Sharpen to a copy of the background layer so that if I later wish to redo it I haven’t altered my original. Doing the sharpening on a copy of the background is the same concept as using an adjustment layer: it doesn’t change the original and can be discarded later.

I sharpen with my image displayed at 100% on the monitor. This is the best way for me to see if any “halos” result from the sharpening. These are the bright edges that look “unnatural” when an image is oversharpened, and if they appear, you need to back off the amount of sharpening until they disappear.

If you’re conservative in the amount of sharpening you use, you won’t have that negative “digital” look that oversharpening produces. You always can add additional sharpening just before printing if you feel that it’s needed to produce the look you want, but, again, I think it’s better to find out whether the image is worthy at the beginning of the workflow. Sharpening will emphasize artifacts that need to be removed and cleaned, and it’s much more comfortable to be doing detailed optimization on a sharp image.

Subjects like these parrot feathers need to be sharp to be effective as a print. Sharpening was done in Photoshop on a separate background copy layer.

George Lepp

One of North America’s best-known contemporary outdoor and nature photographers and a leader in the field of digital imaging and photographic education, Lepp is the author of many books and the field editor of Outdoor Photographer magazine. One of Canon’s original Explorers of Light, Lepp finds inspiration in advancing technology that fuels creative innovation and expression of his life-long fascination with the natural world.