The goal of any sharpening is to create a halo that increase contrast at edges in the image. Darker darks and lighter lights at the edges increase apparent contrast that we interpret as increased sharpness. The trick is controlling the width and brightness of the halos so that they increase edge contrast without making the image look “crunchy”. It’s also worth mentioning that sharpening is not intended (and can not accomplish) to overcome lack of sharpness due to incorrect focus.
Modern sharpening practice is to do sharpening in three separate steps at different times during the workflow:
Capture
Creative
Output
While the screen shots in this series of posts come from Lightroom (LR), the same base code is used in Adobe Camera Raw (ACR) so everything in this, and subsequent posts, applies equally to sharpening in ACR. In subsequent posts in this series I will go into more detail in how to implement Capture, Creative and Output sharpening in LR (and ACR).
Capture sharpening is intended to be a gentle round of sharpening that only compensates for the lost of detail that results from transforming a continuous analog scene into digitized pixels. In Lightroom, capture sharpening applied in the detail panel.
Creative sharpening is sharpening localized to only the portions of an image you want to draw the viewer’s eye to. The most common example of this is the extra sharpening applied to the eyes in a portrait. In LR the local adjustment brush can be used to paint on creative sharpening.
Output sharpening for prints is intended to compensate for printer dot gain. Output sharpening can be optionally applied in the various output modules, e.g., Export and Print. While the controls are few (to none) applying output sharpening is straight froward. We’ll look at how and where this is done in a later post.