
With the latest version of Aperture, Apple has given us more sharpening options. The new adjustment called EDGE SHARPEN gives photographers significantly more control than was available using the standard SHARPEN adjustment.
With Edge Sharpen, only the edges are impacted. This is important because there are times when sharpening an entire image just isn’t required. Who needs a sharp sky?
The main value of Edge Sharpen is that if applied properly, you can sharpen without creating noise.
LUMINANCE
One of my favorite things about this new adjustment is that it works only on luminance, not in the RGB space. Long ago I’d learned the trick of converting images in Photoshop to LAB space so I could sharpen without creating color artifacts. Now I don’t have to do anything. Aperture does it for me.
PERCEPTUAL SPACE
Some of my students have asked what it means to sharpen in the perceptual space. Simply put, this helps to sharpen in approximately equal steps between shadows and midtones.
FALLOFF
And finally, what’s this new slider called FALLOFF? Aperture applies Edge Sharpen in three passes. Each pass uses less intensity than the previous pass. This eliminates halos.
IN PRACTICE
There is no formula that I can give you to sharpen your pictures since there are too many factors involved. But a good rule of thumb is to set the intensity to full blast to see the impact of your adjustments. You can back it off later. Then adjust the Edges slider so you can see what’s being sharpened. Falloff controls how much sharpening is delivered during each pass. I find that Apple’s recommended range of .40 to .70 is a good starting point.
I like to work in full screen mode so I can see how the sharpening is being applied. Experiment, and see what settings typically provide good results. Lastly, don’t over sharpen. It’s tempting but, don’t do it. A little sharpening goes a long way, especially when you’ve made a well-focused photo to begin with.
Photo Copyright Scott Bourne 2005 - All Rights Reserved


Is there a way to have Edge Sharpening come up in the HUD everytime? Right now I have to click the + at the top of the HUD or hit Ctrl-S.
OK, now I am with you. No problem on the typo, I just could not find a setting that was close to 0anything. And since I am pretty happy with the way my images look I was trying to figure out what I was missing. BTW, appreciate your insights Scott.
The amount of edge sharpening required varies by camera, by image, by image use and by taste, just to name some possibilities. Apple's recommended STARTING point for the falloff slider is .40 and .70 sorry for the typo above. Your setting of .69 would be within the recommended starting point. But at the end of the day, if you like what you see, those numbers mean nothing.
I'll correct the entry to reflect the accurate numbers.
Recommendation of .04 to .07 on what? My defaults for edge sharpening seem to be Intensity .81, Edges .22 and Falloff .69 for a Canon 1DMkII -- does it vary by camera or are you talking about a different starting point and range?