> Rob Studdert wrote: > >> On 20 Dec 2004 at 12:00, wendy beard wrote: >> >>> Lon, >>> Can you post it to the list? >>> I have been doing a lot of high ISO shooting recently >>> and am looking for a decent noise-reduction/sharpening >>> technique >> >> Unfortunately attempting to eliminate image noise/grain via the use of >> edge masks gives quite poor results compared to the better dedicated >> noise removal tools. I use edge masking techniques after grain removal >> on occasion but it is really image dependent, the effect can make some >> images look quite un-natural. >> The technique is described in the following link, it's easy to turn >> into an action too, I have mine set so that it stops at the levels >> adjustment layer so that I can control the mask width per image. >> >> http://www.naturescapes.net/042004/ps0404.htm >> >> Cheers, >> >> Rob Studdert
I disagree with Rob, but we all find our own way in the digital maze, don't we? What I find is that sharpening tools and degraining tools work against each other, and routinely use masks to minimize their counter effects.
I don't shoot digital, so in my case, I'm tweaking grain and sharpness loss after scanning film.
I've used these related third party tools: Sharpening: Nik Sharpen, Focus Fixer, PhotoKit, FocalBlade Noise: Neat Image Pro, Grain Surgery, GEM (Plugin, not hardware based).
Here's how I make a sharp/degrain mask, for those who asked how:
Duplicate your color picture document. Convert tne duplicate to Grayscale. Run Find Edges filter on the duplicate. Run Levels on duplicate to get an appropriate initial contrast. Run Gaussian Blur on duplicate to spread edges a tad. Run Levels on duplicate again to fine tune. Result: A sharp mask you can load back into your original image using Select Channel (you select the duplicate file when loading this channel).
Invert this mask to use with grain reduction. I typically use it with Grain Surgery first, early in the work flow, followed at the end by sharpening with Nik Sharpen. You can save the mask as a channel to keep it around for both uses; just remember to invert it as needed.
I've created an action to automate this process. Speeds it up quite a bit. But the Levels and Gaussian Blur steps permit user input; IMHO they need to.
I find the Levels adjustments to be file-dependant; they vary from shot to shot. I often clip the dark end a bunch, then perhaps clip the light end a tad. I often then move the middle gamma slider a bit.
The Blur step is useful, too, as it can be set to protect large areas of fine detail from being degraded during noise reduction by setting Radius to a relatively large value (more than would be necessary to smear out mere grain).
I've also created an action that gives very fat, smooth edges to the mask; I use it when I want the grain reduction and subsequent sharpening to blend into each other subtly. It's many more steps than the simpler technique described above, and I don't use fat edges as often.
Hope this helps.
-Lon
