USM Sharpening Technique.

[sharpfocus]

I learned this method several months ago and I have incorporated it into my digital work flow for images that need it. In my opinion it gives the best sharpening.

1. Open your image in Photoshop
2. Convert to Lab mode, go to> Image> Mode> Put the check on Lab Color
3. Click on layers and make a background copy. All the changes will be done on this layer.
4. Go to your channels palette and click on the lightness channel.
5. Go to your unsharp mask and set the "Amount" at 50% and the "Radius" at 15 pixels. Leave the "Threshold" at 0 and click OK.
6. Go back to your unsharp mask and set the "Amount" to 50% and the "Radius" at 1 pixel and click OK.
7. On the Channels Palette, click on "Lab" to bring back the color.
8. Use the opacity slider on the layers palette to optimize it to your preference. It will adjust from none to maximum.
9. Flatten and convert back to "RGB".
10. Do a "Save as", and you are done.

Sounds complicated but it really isn't. I use it only when necessary. This can be set up as a macro, but you won't be able to use the slider to customize.

Bob

[JohnT]

Thanks for sharing. There seems to be two sharpening methods that are a point of debate among photogs: 1) Sharpening on the Luminosity channel, and 2) Sharpening using the Lab method. Both give very good results IMO, but some folks seem to prefer one over the other and will defend their position till death.

[Duffy Pratt]

Lets say you are sharpening a very light object (say bright yellow letters on a green background). If you do the sharpening in RGB, you might push the light halos to 255,255,255 or close, and the yellow will become white. If you do the same sharpening on the L channel in Lab, you might push the white halo area to something like 100, with overall values of say (100, 0, 20). This is an impossible color that is as bright as the brightest white, but still yellow. When Photoshop converts this back to RGB (when you are through with LAB), it will turn the impossible into something that is possible, and that still has some yellow to it. It's in instances like this that the LAB sharpen is better than the RGB with luminosity.

Duffy

[picasso]

Bobs method above using LAB was outlined in Scott Kelby's (Don't flame me please) latest Digital photography book. I have been using it and it seems to really do a great job.

Paul

[sharpfocus]

Duffy, thanks for the clarification.

Picasso, thanks for giving the credit to Scott. I read it somewhere else on another forum and decided to try it out. I hate the oversharpening artifacts that can show up with using just the usm on the RGB channel. This method eliminates those.

...Bob