Ivan Garcia said:
I am not too sure about my sharpening technique; I’m really struggling with how much to apply.
Any advice on sharpening will be appreciated.
If it looks like too much on screen, then it is
too much.
Generally speaking, the goal of sharpening is to enhance the perception of localized contrast to make the
perception of an image evoke more detail to the eyes.
You can enhance generalized local contrast using a radius of 15 and an amount of 15-30% without sharpening edges (this is great for urban skylines and other similar scenes like mountain landscapes).
You can enhance localized edge contrast for the screen using a radius of 0.5-1.3 and an amount ranging from 180-500% depending on what you sharpend (i.e., 500% on the K/black channel in CMYK may be appropo).
Viewing at 25-50% zoom and using a radius of 3 for sharpening 300 DPI prints is the general rule of thumb. For the amount to use, that really depends on the image.
If you can see halos, you have gone too far.
For a no-brainer approach look at
http://www.thelightsright.com/TLRProfessionalSharpeningToolkit.htm (free) or Photokit Sharpener.
For a first tier exposition on the basics, read
Professional Photoshop: The Classic Guide To Color Correction by
Dan Margulis (there are several versions, get the latest). This is
absolutely without question the only treatise I have read that actually discusses what sharpening does outside of technical computer vision oriented journal articles. The other 99.995% of articles aimed at Photoshop hold your hand and treat you like a toddler. Albeit, I am by training a mathematician with experience is computer vision and software engineering so I am biased against very over simplified approaches filled with lies (i.e., simplifications that damage understanding and intuition). If you want a simpler approach, than look at the TheLightsRight script or Photokit Sharpener. If you want to understand, Read the Margulis text. Margulis' rhetoric is that of an egotistical prick (takes one to know one ;o) and raises the hackles on my back, but he knows his stuff and I respect his writing.
my $0.01,
Sean (my $0.02 is worth $50-$250 and is fairly technical ;o)