Sharpening an image
Video: Sharpening an imageSharpening an image provides you with in-depth training on Photography. Taught by Tim Grey as part of the Lightroom 4 Image Optimization Workshop
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In this workshop digital imaging guru Tim Grey focuses on the Develop module of Adobe Lightroom 4. Starting with an overview of the image optimization workflow in Lightroom, Tim walks you through the process of evaluating your images and deciding what adjustments you need to make. He teaches you how to use the Develop module's presets to achieve quick results, as well as how to apply your own adjustments, from simple exposure and color adjustments to advanced options like the Tone Curve and the Graduated Filter tool. Learn techniques for cleaning up your images, applying creative adjustments, and duplicating adjustments across multiple images. Finally, get some tips for integrating Lightroom and Photoshop to create panoramas and high dynamic range images.
- Evaluating images
- Seeing a before and after view
- Correcting mistakes with the History and Snapshot features
- Develop module basics
- Fine-tuning with the Tone Curve
- Sharpening an image
- Painting adjustments into an image
- Image cleanup
- Creative adjustments
- Duplicating adjustments
Sharpening an image
If you're like me, you probably put a lot of emphasis on trying to achieve a sharp image in the camera. That includes things such as using a tripod, maybe making sure you're shooting with a fast enough shutter speed. Checking your depth of field very carefully, and most importantly checking for critical focus. Even if you take the utmost care in achieving a sharp result. However you'll still need to apply a little bit of sharpening in order to compensate for a variety of things that affect the perceived sharpness or detail in an image. Lightroom includes some sharpening controls that allow us to compensate effectively for the capture itself. The issues that relate to the camera's processing of the information it's recording that can cause a little bit of a loss of sharpness. Let's scroll down to the detail section of the the Right panel in the Develop module, and we can take a look at the various sharpening controls. The preview in the detail section defaults to a 100% zoom, we can also zoom out if we need to see a little bit larger area of the image. We can then pan around for example and then click to get back to a 100% view. Or we can still continue panning around the image as needed. We can also choose a particular area of the image that we want to view by clicking on this little target button.
And then clicking in the image itself in the area that we want to evaluate. That will set that portion of the image as the area being previewed. We can then turn our attention to the four sliders that allow us to control sharpening. The first is Amount, which determines how much sharpening, the strength of the sharpening being applied to the image. As you increase this value you'll see that contrast at a localized level is being increased. I'll go ahead and click on the image it's self so we can take that image to a 100% view.
And you start to get a sense of just how much sharpening is being applied obviously, far too much in this case. I'm going to leave that amount at a relativealy high value for the moment though. So we can explore the other settings and better see how their effecting the image. When we apply sharpening to an image, we're obviously adding contrast. We're just adding that contrast at a very small scale, perhaps just one pixel across for example. But we can adjust the radius, which is the size of the contrast area enhancement. If I increase the radius, you'll start to see some more clear indications of that sharpening effect. Potentially you can start to see some halos some glowing areas around high contrast portions of the image.
But Lghtroom actually limits us to a relatively modest radius so in most cases that's not going to be a significant issue. The detail slider determines how much fine detail is being sharpened. In other words are we applying sharpening to every single nook and cranny in the image even if there's only a subtle difference in values between pixels. Or are we only sharpening the areas of relatively strong contrast? If I move the slider to the left you'll see for example the background area remains a little bit smooth. And if I move that slider over to the right you'll see that every single pixel in the image seems to be getting a Sharpening effect. The Masking control allows us to focus the sharpening on just the edges within the image.
In other words the highest contrast areas of the photo. I'll go ahead and increase this value, and once again you'll see that the sharpening dissapears for large portions of the photo. We're essentially focusing that sharpening in on only the highest contrast portions of the image. Ofcourse these concepts are all well and good, but the real question is, how do you go about actually applying sharpening? Well there is a preview option that makes it much easier to see the effect. I'll go ahead and reduce the values for these other sliders. An, in fact, reduce amount just a little bit.
And then we'll take a look at the preview option for each of these controls. If you hold the Alt key on Windows or the Option key on Macintosh while adjusting the amount slider, the preview will change to a gray scale version. And this makes it much easier to see the actual effect of that sharpening. I'm going to leave the amount, again, at a somewhat exaggerated value so that we can better see the other adjustment controls here. I'll once again hold the Alt or Option key, while adjusting radius. And now you can get a sense, of the size, of that Sharpening effect.
At each high contrast edge, we can see that with a large radius value. The effect is spread out over a relatively large number of pixels. Not a huge area but still larger if we moved to the right and a smaller area if we moved to the left. With fine detailed subjects you'll generally want to use a relatively low radius setting. Typically one pixel or less. With relatively smooth transitions of contrast in the image you might want to increase that radius setting just a little bit. Next we'll look at the Detail slider, and here again we're specifying how much detail within the image should be sharpened.
Holding the Alt or Option key again we can move the slider to the right and see the relatively high amount of detail being brought out in the image. If we move over to the left, we'll see that only the strongest details in the image are getting that sharpening effect. And once again, with the masking slider. Holding the Alt or Option key once again. As I increase the masking value, you'll see that we're narrowing in the Sharpening effect to only the highest contrast edges within the image. And of course, moving to the left, we'll start to see the Sharpening effect in broader areas of the image.
Generally speaking, the approach I'll take with sharpening here is to increase the amount relatively signifigantly. And then fine tune the radius to get the best value there. Bringing the amount slider back down to a more appropriate value, once I've defined a good radius. I'll then adjust detail and masking if I need to mitigate the sharpening effect in certain areas of the image. For example, keeping a low detail, and high masking value. If I only want to sharpen the highest contrast areas of the image or increasing the detail slighther if I want to see a lot of fine detail. It depends on large part on your preference as well as on the nature of the image itself.
In all cases though I strongly encourage you to apply relatively modest sharpening when you're working on the image at this stage. You can always apply additional sharpening at export with that sharpening based on the actual final output size and the output conditions. For example a web gallery versus a print would call for different final sharpening. So think of this as just compensating for the initial capture and optimizing the appearance of the image at this stage of your workflow.
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