there are two threshholds you must discover and they are based on your image size in pixels. these are the numbers i find best for images at around 20 megapixels. i use a deblur of 1.7 and a threshold of about 10. the images must have some in-camera sharpening already (or sharpened a little through your RAW editor) or the filter makes things worse. first, the threshold should be as low as possible without artifacts appearing in smooth areas. then, start with the deblur at 0. slide it right slowly using the spin buttons and watch the preview. it should get gain contrast for a little bit, then lose contrast, then gain contrast and then lose contrast again. you want to leave it at the second point where it has gained contrast or slightly past it to the right. much more than that and it begins to build strange whorls in the image. adjust the threshold while previewing a smooth area in the image to make sure that there aren't too many artifacts. too high a value and it begins to posterize the image. start with 0 and work your way up. check the results by examining other areas where there are smooth tones.
Herb.... ----- Original Message ----- From: "Rob Studdert" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, October 24, 2003 9:57 AM Subject: Re: Unsharp Mask > I ran it today for the first time and I must say I'm baffled regarding the > results. I ran it on an un-edited low compression 4Mp jpeg and regardless of > the settings it seems to totally butcher the image. The threshold at any point > other than 100 creates nasty grey posterized areas across highlights and even > with deblur set to 0.1 high contrast edges acquire a nasty dark edge. Any > hints?
