Sharpening options

[DirtyLittlePuppy]

Pekka is adding features faster than I can absorb them (overwhelmed little puppy)

Can someone explain how "sigma" fits in to the sharpening equation for Imagemagick?

Pekka, what is your sharpening workflow?

I am using a 10D, Capture One LE saving unsharpened image, in PhotoShop 6 applying Pekka's action "do normal sharpening and saturation" to get a finished image. Should it then be resized to the largest desired web size for uploading?

What sharpening options and compression are people using?

Why the remove profile option? I understood web pics should have sRGB.

[Pekka]

DirtyLittlePuppy wrote:
Pekka is adding features faster than I can absorb them (overwhelmed little puppy)

Can someone explain how "sigma" fits in to the sharpening equation for Imagemagick?


Here's how ImageMagick folks explain it:

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The -unsharp option sharpens an image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 to have the method select a suitable radius.

The parameters are:
radius: The radius of the Gaussian, in pixels, not counting the center pixel (default 0).
sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
amount: The percentage of the difference between the original and the blur image that is added back into the original (default 1.0).
threshold: The threshold, as a fraction of MaxRGB, needed to apply the difference amount (default 0.05).

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Pekka, what is your sharpening workflow?

I am using a 10D, Capture One LE saving unsharpened image, in PhotoShop 6 applying Pekka's action "do normal sharpening and saturation" to get a finished image. Should it then be resized to the largest desired web size for uploading?


For daily use I use C1 + soft sharpening with zero treshold and then may add USM .8/75 in PS. Or use incremental sharpening as in my action. I'm thinking of getting Photokit Sharpener for occasions when I need to have the absolute most out of the files (Capture 1, Neat Image 2.6 Pro and Photokit Sharpener sounds to me like the ultimate workflow for RAW now)

Why the remove profile option? I understood web pics should have sRGB.


"Remove profiles" command removes EXIF and IPTC data but as I understand it in newer IM versions it tries to preserver color profile information. Removing EXIF and ITPC is very important especially for thumbnails, because if you don't do it you can never get e.g. microthumbnail file size under 10-15KB. With remove profiles it's about 1KB.

You should convert your originals sRGB or "unprofiled" (practically same thing). Profiles are not usually read in