Lookin' Sharp

Sharpening your images is another step from capture to output. Just like exposure, clarity, cropping, and other adjustments, sharpening plays an important role in the creative process. But when should you apply sharpening? How much should you sharpen? What does sharpening do? Let's take a look at sharpening and how Lightroom handles the process.

Even if you have the best glass and your focusing system is top of the line you cannot avoid the introduction of some softness during the digital imaging process. To start, the sensor converts analog light to digital information when you press the shutter release. That conversion introduces a degree of softness to the RAW file. You won't see this in a JPEG since the camera will sharpen the image while cooking the JPEG. More softness will get introduced when printing the image. Even though modern ink jet printers have very high resolutions, we are still spraying ink onto some medium. So there are several parts of the process that impact the sharpness of the image.

Now is probably a good time to make a distinction between focus and sharpness. There are many things that can result in an out of focus or blurry image. Camera shake, subject movement, incorrect focus point used, slow shutter... and list goes on. Let's be clear up front. No amount of sharpening can bring an out of focus image into focus. That's not what sharpening is for. (That's what focusing is for.) So we need to pay attention and get the focus right in camera.

There are three distinct points in your workflow that sharpening can be applied:

  • Capture Sharpening: Sharpening applied when first importing/opening an image to counteract softness introduce by the digital imaging process.
  • Creative Sharpening: This is sharpening applied to selective areas of an image for creative or artistic purposes.
  • Output Sharpening: Each output medium introduces some level of softness to an image. Output sharpening prepares an image so that it retains its sharpness once it reaches its final output destination.

Creative sharpening can be an entire discussion by itself and we'll leave it for another time. I would like to point out, however, that Lightroom does have this capability via the Adjustment Brush tool. You can set levels of sharpness and paint those in selectively. If you really want to get creative with sharpening I recommend you bring the image out to Photoshop when you have a much greater array of tools at your disposal. For now, though, let's look at the sharpening tools available in the Develop module, how they work, and how they apply to Capture and Output.

Capture Sharpening

Lightroom's default settings provide a basic level of sharpening when an image is imported into the catalog. Those settings are derived from the camera profile used for the image. They are slightly different for RAW images and JPEG/TIFF images.

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Whether or not to apply any sharpening at the initial stages of image processing is a matter of personal preference. There are many photographers who do not like to introduce any sharpening until the end of the process while others like the concept of capture sharpening to bring the image back to base state before continuing. Whatever your preference, you can tweak these settings before you start to process the image.

The Detail Panel

Lightroom's sharpening controls live in the Detail panel in the Develop module.

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There are two important things to note here. In order to see the effects of the sharpening settings you must be viewing your image at a minimum of 100% or 1:1. If you aren't then the warning triangle with an exclamation point will appear on the upper left of the panel. Simply click this and your image will be zoomed in to 1:1.

Secondly, if your panel looks like the illustration above, click on the small dark triangle on the upper right of the panel to view the full panel.

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The target tool (small crosshair square in the upper left) can be used to choose what part of the image shows up in the detail viewer. You can also drag the viewer image around to other areas of the image.

There are four sliders available to adjust sharpening in the image. The Amount slider is the basis of sharpening. Setting this to 0 turns off sharpening. Sharpening looks for areas of higher contrast and applies the indicated amount to those areas. Usually the highest amount of contrast appears along edges in the image. By increasing the contrast here the image will appear sharper. The range available is 0 to 150.

The Radius slider determines how far out from the edge (in pixels) you want to apply the contrast boost. Be careful here. If you have a lot of fine detail in the image a small setting may do best. If you have large details then a larger setting may be better. This slider ranges from 0.5 to 3.

Our next slider, Detail, deals with frequency in the image. Lowers settings will concentrate more on the edges while higher settings increase what areas are sharpened. Higher settings are good for bringing out textures in the image. Detail ranges from 0 to 100.

The last slider lets you control where all this sharpening goodness gets applied. Masking will mask out areas of the image and prevent sharpening from being applied. At 0 sharpening is applied everywhere (i.e. - no mask is applied). The higher this slider is set the more the image is masked. As you increase the amount the mask looks for edges and concentrates the sharpening there. At 100 all but the most prominent edges are masked away.

A very useful key when sharpening is the Option key (ALT in Windows). If you hold this key down while adjusting the sliders, Lightroom will show you a more targeted view of what that slider is doing. For Amount you will see only the luminance channel. This removes the distraction of color and lets you see what impact the amount is have. In the case of the Radius and Detail sliders, a high pass filter view is shown. Masking will reveal the mask being applied. White areas allow sharpening, black areas are masked away. Here are some examples.

optamt.jpg

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The Option key (ALT in Windows) is also useful when you want to start over. When you press this key the word Sharpening will change to Reset Sharpening in the panel. Click Reset Sharpening and all the sliders will revert to their initial states. If you want to reset only one slider then double click on its name to the left of the slider.

Output Sharpening

Different media introduce different levels of softness. The purpose of Output Sharpening is to counteract this. Once we have sharpened the image to our liking further sharpening may be require. Lightroom provides output sharpening in several areas. In the Print module you can choose from Low, Standard or High and Matte or Glossy paper. Of course you can turn it off altogether if you like. Certain engines in the Web module let you choose between Low, Standard, and High. In the Library module, the Export dialog has an Output Sharpening section with the same array of choices.

Another method that can afford greater control is to do your output sharpening using the Detail panel and forego the output sharpening built into these other areas. If you choose to use this workflow, I recommend you get your image to the state of sharpening you like. Next create a virtual copy for the output medium you will use and apply sharpening settings appropriate for that medium. The advantage here is that you can exercise greater control and you can maintain a different virtual copy for each medium. Having that copy makes it easier to repeat a print you like.

This article is not anywhere near a definitive and comprehensive look at sharpening in Lightroom. If you want to dive deeper into the sharpening waters I heartily recommend and article by Seán McCormack in the October/November 2009 Photoshop User magazine entitled Sharpening With Lightroom. If you can't find that issue don't despair. I have it on good authority that Seán plans on posting the article to his site, Lightroom Blog, very soon so keep an eye on that! UPDATE! Seán has posted the article. Click here.

For an even deeper dive into the whole topic of sharpening get yourself a copy of Real World Image Sharpening with Adobe Photoshop, Camera Raw, and Lightroom (2nd Edition) by Bruce Fraser and updated by Jeff Schewe. This is a definitive work and quite comprehensive.