The vast majority of photographic images benefit from sharpening. Before you decide how and when to sharpen images, you need to decide why you’re sharpening them. The goal is to enhance detail rendition without producing distracting visual artifacts. You’ll find many conflicting philosophies and their accompanying strategies for sharpening images. The seemingly conflicting advice can be hard to reconcile.
Should you sharpen once or multiple times? Should you sharpen differently for different subjects? Should you sharpen differently for different sizes? Should you sharpen differently for different presentation materials or supplies? Should you view your files at 100% or 50% screen magnification?
Capture source, output device, substrate or presentation device, presentation size, subject and artistic intention all play a role in sharpening. The characteristics and solutions for many of these factors can be objectively defined for everyone; at least one of these factors—perhaps the most important, your artisti vision—only can be decided individually.
So, if sharpening is a complex subject, how do you simplify your sharpening workflow to one that’s practical without compromising quality?
Bruce Fraser and Jeff Schewe offer the best advice in their definitive volume on sharpening, Real World Image Sharpening with Adobe Photoshop, Camera Raw, and Lightroom, which is highly recommended reading for every photographer. Instead of sharpening your images for you, they teach how to sharpen.
Their philosophy of sharpening is perhaps the soundest in the industry. They recommend that images be sharpened in a progression of three stages: once for capture sharpening, a second time for creative sharpening, and a third and final time for output sharpening. The objectives and methods of each of these stages vary considerably. When mastered, the whole process can be streamlined to achieve sophisticated results in minimum time.
Capture sharpening is something almost all images can benefit from. It compensates for inherent deficiencies in optical and capture systems. All lenses and sensors have deficiencies. They don’t all have the same characteristics or deficiencies.
General parameters for ideal sharpening settings can be determined for all images created with the same lens/chip combination. You can speed your workflow by determining settings for a best starting point. You may need to modify these settings somewhat to factor in additional considerations, such as variances in noise (ISO, exposure duration, temperature), noise-reduction settings and the frequency (or frequencies) of detail in an image.
Capture sharpening needs to be determined visually, while previewing an image on a monitor at 100% screen magnification, the magnification that most precisely displays low-frequency detail such as texture and noise.