One of the most important steps in post-processing is sharpening, and whilst it may seem simple, it is a process that is actually rich with complexities. I noticed that this forum doesn't have a dedicated thread or section about sharpening, yet questions about sharpness and sharpening appear every day. I thought it'd be nice to get everything in one place.
So this thread is the place to post your vast wealth of knowledge about sharpening. Here, we'll cover everything from the basics to the highly technical complexities.
The things I'd like to cover in this thread (with the help of your contributions) are:
- Capture vs Creative vs Output sharpening
- Different sharpening techniques (e.g. USM, high-pass overlay)
- Sharpening for different types of images
- Tailoring your sharpening to your final display medium, i.e. output sharpening (web, print, canvas, poster, etc).
- Anything else related to this fascinating but difficult process!
I'll start us off with a couple things:
- There are really 3 sharpening steps in PP. Capture sharpening takes place at the beginning, and brings back any sharpness that was lost in capturing a photograph, e.g. because of the AA filter. Creative sharpening takes place during PP and is used to do things such as accentuate features such as eyes and control contrast locally. Output sharpening takes place at the very end, and what happens here depends entirely on your final display medium.
- USM (un-sharp mask) is the most popular sharpening technique. Canon recommends (for some cameras) starting with 150%, 0.3 pixels radius, threshold 0.
- Another popular method is the high-pass method. Here a very weak high-pass filter is applied on a new layer, and then the layer is set to overlay. I really like this method.
Hopefully this thread can grow and provide lots of useful information on sharpening.
Perhaps someone could start by writing a bit about sharpening for web, e.g. for displaying images on this forum?
Edit: I've learned a ton from this thread since I started it. I still do my capture sharpening in ACR, but I use the masking and detail sliders now by holding down the option/alt key - you get an amazing amount of control in ACR alone. I've also switched to smart sharpen on a separate layer (so I can make layer masks or reduce opacity) as my preferred output sharpening method over the high pass method. I no longer touch USM unless I'm using it for defogging.
I recommend that newbies read through this entire thread. Tons of different methods are covered and continue to be covered, using a variety of software.