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Ask An Expert: Photoshop Unsharp Mask Vs. Lightroom’s Sharpening Tool

January 19, 2010

Today’s “Ask An Expert” question is an outstanding one.  I’d never given much thought to the difference in sharpening an image using unsharp mask in Photoshop vs. using the sharpening tool in Lightroom.  Apparently Nat Coalson hasn’t only given it a lot of thought, he’s developed some really solid logic behind why you should use Lightroom to sharpen your images.  Nat is an Adobe Certified Expert and the author of Lightroom 2: Streamlining Your Digital Photography Process.  He’s also co-leading our “Wildflowers and Reflections in the Tetons” workshop June 10 – 13, 2010.  Here’s the question I received and Nat’s thorough response.

The Question:

How does the sharpening in Adobe Lightroom compare to unsharp mask sharpening in PhotoShop. I have heard several people claim it is good to use for capture sharpening for images submitted to agencies that will be licensed by clients who will then resize and do additional output sharpening.

What is the difference in Lightroom sharpening and Unsharp mask??

Nat Coalson Responds:

The sharpening on Lightroom’s detail panel is very different from Photoshop’s Unsharp Mask.

Unsharp Mask was developed many years ago in the early days of digital imaging. Though it has been the de facto standard on which many other methods of sharpening are based, it’s crude in comparison to newer algorithms, and can produce destructive artifacts relatively easily.

On the other hand, Lightroom’s sharpening is designed to be “gentler” in it’s application, and will produce fewer haloes and other artifacts if used properly.

Modern sharpening workflows involve several steps of sharpening, unlike older techniques of the past, when it was believed that the optimal amount of sharpening could (and should) be done in a single pass.  These days, sharpening is broken down into three stages: capture, creative and output.

Capture sharpening overcomes the loss of sharpness resulting from the pixel grid itself. Every digital image capture suffers from some amount of softening as a result of the real, organic world being mapped to a discrete grid of pixels. The sharpening on the Detail panel is intended to be capture sharpening only and to simply overcome this inherent loss of sharpness.

Creative sharpening is used to enhance specific areas of the image.  Lightroom’s local adjustment brush provides the ability to “paint” on sharpening in localized areas.

Finally, output sharpening is applied when the file is Exported or printed. Output sharpening is applied using the appropriate method and strength for the inteded output destination. For example, if you’re printing to a matte fine art paper, you would apply more sharpening than if printing to a glossy coated paper.

My default settings for sharpening on the Detail panel:

Amount 60 > The strength of the sharpening to be applied.

Radius 1.1 > The width of the sharpening along the “edges” of contrast. For images with lots of fine detail, I might go down to .8 pixel radius, and increase the Amount. Images that don’t have lots of fine detail might go up to 2.0 radius, but never more than that.

Detail 50 > Similar to radius, if the photo has lots of fine detail, use higher levels of Detail.

Masking 15 > Masking restricts the application of sharpening from being applied to areas of smooth, solid color and limited contrast. For example, blue sky or the skin in a portrait usually should not be sharpened; masking keeps the sharpening from being applied to these areas.

For all the controls, holding the option or alt key while moving the slider will show you a grayscale preview of the effect being applied.

To see the sharpening previews on the image itself, you need to be zoomed in to 1:1 or greater.

I usually fine tune these settings on an image by image basis, but these settings will give me close to the ideal amount of sharpening to begin my processing, on the majority of images.

I often apply standard or high levels of output sharpening, too.  Though there’s not a lot of direct control over this in Lightroom, the levels of output sharpening they’ve included work pretty well, and are very simple to apply.

All of this is based on raw capture; if you shoot JPG then some sharpening is already applied in the camera, and the settings would be different. (But in the Lightroom workflow, there is no reason to ever shoot JPG!)

If you do as much of your work as possible in Lightroom, you may find that you never need to go into Photoshop, especially for sharpening.  Though there will be special cases and images that need the pixel-level editing that Photoshop provides, using Lightroom’s sharpening options properly may be all you need.

Share your techniques for sharpening in Lightroom and/or Photoshop in the comments below.  Someone just might learn something and that’ll send good karma your way.  We can all use a little extra good karma!

17 Comments leave one →
  1. Jim Casteel permalink
    January 19, 2010 9:47 am

    I have tried these standard sharpening settings on several of my landscape images and have noticed that it almost causes a watercolor-painting look to the detail when you zoom to 100%. I am not completely sure this is what it is supposed to look like. When I am not zoomed to 100% it looks great though. Any suggestions?

  2. January 19, 2010 10:21 am

    Thanks guys! It’s nice to hear these things stated so clearly. Am I correct that all this applies in ACR 5 for those of us who are unfortunately without Lightroom?

  3. January 19, 2010 12:09 pm

    This is the best and most clear explanation I have read. I have found that Lightroom sharpening is great way to go for images that will be going to agencies/portals or my own website for downloading and licensing. Sicne there is no way of knowing how these will be used or at what size correct capture sharpening is critical.

    Allen Russell

    • January 19, 2010 12:13 pm

      Allen: I’m glad you found Nat’s answer helpful. I learned a lot in reading his response. I had no idea what masking did until now. Guess I’ll be using it more going forward.

  4. January 19, 2010 12:36 pm

    Jim – the watercolor look you’re describing is likely caused by a combination of Amount and Radius settings being too high. In cases where you’re using high amounts (say, 50 or higher) you might need to use a smaller radius.

    Jackson – yes, ACR 5 and up has the same sharpening controls and algorithms as Lightroom 2.1 and higher.

    Lightroom 3 and ACR 6 will have new, improved sharpening algorithms.

  5. kurtbudliger permalink
    January 19, 2010 1:06 pm

    Jason, yes sharpening in ACR is just like Lightroom.

  6. kurtbudliger permalink
    January 19, 2010 1:07 pm

    Oops, Nat and I must have been commenting at the same time, cheers and great post!

  7. January 19, 2010 3:05 pm

    Nice Posting and Good to see this, I think, This is best technique…

  8. January 19, 2010 9:10 pm

    Very useful and informative. Thanks Bret and Nat. I have avoided using the sharpening algorithm in LR2 beyond it’s defaults due to the fact that I simply don’t fully understand it as well as I do with Photoshop’s Smart Sharpen…

    I remember reading somewhere that the default 25 amount in Lightroom that is applied whenever a RAW file is uploaded is the equivalent of 0… is that true?



    • January 20, 2010 12:42 pm

      Good question Mac. I don’t know the answer. Hopefully Nat will check in & respond. Glad you found the article useful!

  9. January 21, 2010 9:48 am

    Great info, I never thought that much into sharpening but need to

  10. January 26, 2010 1:01 pm

    Mac – no, 25 is not zero. 0 is 0. To fully disable LR sharpening you need to use 0 for Amount.

    The sharpening defaults of 25, 1.0, 25, 0 can be overridden, too. If you have settings you like better, you can save them as a Develop preset and then apply them either on Import or from within the catalog. You can also save your own new global settings, in the Develop module under the Develop menu > Set Default Settings. Note that changing the defaults won’t affect any photos that you’ve already adjusted their settings; the default applies only to photos for which you haven’t changed those particular settings.

  11. May 11, 2011 3:34 am

    Update: with Lightroom 3 and the new 2010 Process Version, the effects of the Detail panel sharpening adjustments are much more pronounced. With this in mind, my new defaults are:

    Amount 35
    Radius 1.0
    Detail 15
    Masking 15

    Also, Clarity (on the Basic panel) is stronger in the 2010 Process Version so I’ve lowered that default to 10.

  12. mortenboeriis permalink
    November 1, 2011 1:47 pm

    How about this slightly softer but very clean look (LR3.5)?
    Amount 135
    Radius 1.0
    Detail 0
    Masking 0
    Is that too subtle? I kinda like the quite unprocessed look while it is still sharp.


  1. Valuable Internet Information » Ask An Expert: Photoshop Unsharp Mask Vs. Lightroom's Sharpening …
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  3. Improved Image Sharpening in Lightroom 3 & Adobe Camera RAW 6 — A.J. Wood - Adobe Instructor

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