Help I have two SHARPENING questions

[nich0024]

Working in LAB and using Unsharp Mask are similar in what way?

and..

Sharpening by using layers and the blending modes allows us to control which two things independently of each other?

Thank you for any help!!

[Colin Southern]

I'd be glad to help, but unfortunately, I'm afraid that the questions seem more like a cryptic crossword clue.

With regards to sharpening, in LAB mode you can sharpen the luminence channel more agressively because it won't increase colour noise. I may sharpen on a seperate layer (for safety), but blending modes don't normally enter into the sharpening side of things for me.

[herbert]

I'd be glad to help, but unfortunately, I'm afraid that the questions seem more like a cryptic crossword clue.

Or the homework from a photography course...

[The Blue Boy]

Is this a test?

I'm with Colin in the respect that I use neither of these methods.

[Hansm]

LAB has it's advantages, but you have to get used to it.
Sharpening in LAB is best done in the L channel only.
The A and B channel are to be used for colour adjustments etc.
I worked some time in LAB but don't do this that much anymore.

[ANSORB]

Working in LAB and using Unsharp Mask are similar in what way?

and..

Sharpening by using layers and the blending modes allows us to control which two things independently of each other?

Thank you for any help!!

By your second question I wonder if you are thinking about the two types of halos, light and dark, which USM produces (and all sharpening methods as far as I know). As the light halos can be more objectionable than the dark it is sometimes suggested that you have them on seperate layers, with the light halos uppermost, and just reduce that layer's opacity. Assuming have done everything else you want to and flattened the image the sharpening workflow goes like this:

1.Duplicate the background layer and apply USM with the settings you want
2. Set the new layer's blending mode to Darken That hides the light halos. Call the layer "Darken"
3.Duplicate the Darken layer and set the blending mode to lighten. That reveals the light halos again. Call this layer "Lighten"
4. By lowering the opacity of the Lighten layer you can reduce the brightness of the light halos so they become less objectionable.

I don't use it as often as I used to because I use Focus Magic for most images. But the above workflow is simple to do and it does work.

[Viana]

Save your completely adjusted photo in Photoshop with all layers in case you want to do something different later. Lock that photo.Sharpening is typically the very last thing you do prior to exporting the completed photo. The Lab Mode method of sharpening in Photoshop is preferred by many people. It gives much cleaner edges because it uses the luminance/brightness channel rather than affecting all of the colours: Click on Image, then Mode drop down menu, then click on “Lab Color.” You will be asked to flatten the image.Go to the channels/layers panel (on the right) and click on “Lightness.” This will turn the photo B & W. Then go to the “Filters” drop down menu and click on “Unsharp Mask” amount 120%, radius 1 pixel, Threshold 3 levels. Then return to the “Image” menu and click on RGB color to restore the colour. These amounts are not set in stone. It depends on the photo. You can play with the sliders to lessen or try making two passes if one is not enough. There are tutorials all over the web for this method. Once you have sharpened export the photo with "Save As". Close the photo without saving to not overwrite the PS adjustments.

[Colin Southern]

Or the homework from a photography course...

Never crossed my mind

[Colin Southern]

Sharpening is typically the very last thing you do prior to exporting the completed photo.

Not really I'm afraid. You'll need at least 3 passes for optimal results. Capture sharpening to counter the softening of the digitisation process, demosaicing process and the anti-aliasing filter (which is pretty much the first step post RAW converter) - content/creative sharpening (which can pretty much be done at any stage in the workflow), and output sharpening (which is pretty much the last thing, and done after any final resampling) to prepare the image for the output device.

I wrote a little about it here and here if you're interested. And if you're a real glutton for punishment, (the late) Bruce Fraser and Jeff Schewe wrote an excellent book on the subject.