Photographers are always concerned about what’s in focus - making certain that in-focus areas are tack sharp and when using limited depth of field, that out of focus areas are pleasantly blurred. There is no shortage of advice on how to do this in-camera via careful shooting techniques. Here we will look at the ability to emphasize detail post-capture.
It's important to understand up front that the techniques covered here will not turn a blurry mess into a razor sharp masterpiece. Digital processing does, however, offer a number of options for modifying the appearance of detail.
Enhancing or suppressing detail essentially revolves around increasing or decreasing contrast within the image, whether it’s luminosity or color-based contrast. The key lies in how and where the contrast adjustments are applied. The challenge when attempting to emphasize detail is to avoid also emphasizing image noise. Care must also be taken of course to maintain a natural, believable result.
In this article I will explore techniques for enhancing detail using a single image. We’ll use tools that are common to most major image editing software as well as plug-ins from Nik Software and Topaz Labs. While there are certainly other tools available, these examples can serve as jumping off points for you, no matter which application you use.
Clarity and Definition sliders
We’ll begin with the Clarity slider, which is found in both Adobe Camera Raw (ACR) and Lightroom (LR) and the Definition slider used in Aperture. These sliders can be used to increase (or also decrease) localized midtone contrast, meaning that the effect is aimed primarily at 'flat' areas of relatively modest contrast. Furthermore, these tools seek to apply a rather gentle adjustment that avoids setting pixels to either pure white or pure black, which would actually obscure detail.
You can see this by watching the histogram change as you pull these sliders from one extreme to the other as shown in the image below. The distribution of pixels changes so that pixels are slightly shifted away from the midtones towards the extremes, which increases the midtone contrast. Visually these tools can add the illusion of increased sharpness as well as a slight saturation boost. Used to an extreme, of course these sliders can create artifacts, but used properly, they can seem almost magical.
Below you can see a single image and histogram both before and after some localized midtone contrast adjustments. No other adjustments have been applied.
|Image with no adjustments||Histogram with no adjustments|
|Image after using the Defnition slider||Histogram after using the Defnition slider|
|Image after using the Clarity slider||Histogram after using the Clarity slider|
To apply this effect to specific parts of the image in ACR or LR, use an Adjustment Brush and set the Clarity value as desired. Note that you can set a negative value for the slider and this will reduce the details. This provides the option of enhancing the appearance of detail simply by applying brush strokes with a negative Clarity value in background areas; the detailed areas, by comparison will appear to be 'more' detailed. In Aperture you can paint in the Definition adjustment wherever you like, to increase detail. In order to decrease detail go to Brushes > Blur and paint over the areas you wish to appear less sharp.
Plug-ins for detail modification
For even more control over details, Nik Software's Color Efex Pro 4 (CEP4) plug-in includes several contrast adjustment filters. Topaz Labs also produces plug-in effects that can adjust contrast. Many other tools exist, of course, but these are the ones that work for me and should give you an idea of what’s possible. It's worth repeating that any of these tools can create extremely un-natural results, but when used with a light hand, they can improve your image significantly.
Nik Detail Enhancer
The first filter I often turn to to enhance detail is Nik’s Detail Enhancer. This filter is new to CEP4 and one that I find I am using frequently. As the name implies, it emphasizes details throughout the image. Set the Effect Radius controls to Fine to bring out as much detail as possible, Normal for a moderate amount of detail, and Large to emphasize just the larger details. Which one is best depends on the particular image, but you can see how this setting changes the results in the examples below. The Detail Extractor (DE) slider is the main control or 'throttle' determining how much detail is emphasized, then you adjust the Contrast and Saturation sliders to taste. You can use the Control Points to apply the Detail Extractor just to localized areas or to temper it’s effects elsewhere. Note that in the final image I’ve used a Large Radius setting but decreased the DE significantly.
|Original Image||Detail Extractor set to Fine|
|Detail Extractor set to Normal||Detail Extractor set to Large|
|Final image, Reduced DE slider for subtly increased detail|
Nik Tonal Contrast
A potential disadvantage of the Detail Extractor is that it accentuates details throughout the tonal range. Sometimes you’ll want to bring out details not based on their size, but by their tonal value, so that you can adjust details independently in the highlights, midtones or shadows. I use Nik’s Tonal Contrast filter for that. When you first open this filter, by default the highlight and shadow sliders are set to 25 and the midtone slider is set to 50.
Sometimes this is effective but other times I find it’s a little too strong if I want to maintain a realistic looking image. By adjusting the sliders individually you can quickly and easily enhance details throughout the image. Use control points to limit the effect to specific geographic portions of the image. In the example below, I mainly opened up the Shadow Details to restore detail to the foreground. I subtly added to the midtone and highlight details to maintain a realistic look to the dramatic clouds and lighting.
|Original Image||CEP 4 Tonal Contrast|
Nik Contrast Color Range
The other Nik filter I often turn to is Contrast Color Range, to increase the awareness of various color details in an image. The sliders in this filter are a little less intuitive to use, but overall they enhance or reduce the contrast among the colors in the image by lightening a target color and darkening its complementary color. This can help isolate or blend objects and details within the image depending on their color. It’s easier to use than it sounds. I begin by decreasing the default overall Contrast slider. Next I make sure the Color Contrast slider is set to about 75%. (That way it’s easy to see what colors are being affected.)
Next I adjust the Color slider to choose the “key” color, which is the color that will get lightened. The complementary color of the key color will darken. You can make this choice based on the visual results as you move the slider since the image often will change substantially. Then I adjust the Contrast Color slider to adjust the strength of the effect, and then tweak the overall Brightness and Contrast sliders. In the example below, note the separation of colors in the foliage after applying Contrast Color Range.
|Original Image||CEP 4 Contrast Color Range|
Topaz Detail 2
Topaz Labs offers several filters that enable you to modify the details in an image. Most Topaz products share a common user interface. On the left there are various presets and as you scroll over them, the preview above changes. In the center is the image showing whatever changes you’ve applied or the initial image. On the right is a navigator and various sliders to allow you to tweak each parameter. As you hover the cursor over each slider a tool tip appears explaining the function of the slider. But often the most effective way to set the sliders is to experiment by pulling them to extremes and then scaling back, always paying attention to how the image changes.
Topaz Detail 2, is a plug-in devoted to detail enhancement or suppression. There are numerous presets for emphasizing details or smoothing out details that serve as good starting places. On the right side of the interface there are six sliders. The Small, Medium, and Large Detail sliders allow you to determine what areas are considered as small, medium or large details. A quick pull of the sliders to the extremes lets you see what this means for your particular image. The associated Boost sliders then accentuates (or suppresses) these details. Often a very light hand is helpful with the Boost sliders.
Be particularly careful with the Small Boost slider because it can aggravate any noise issues present when pulled to the right - of course moving it to the left can reduce some noise, but it may remove details as well. Topaz Detail 2 contains additional sliders to let you modify the overall brightness and white balance, as well as to protect highlights and/or shadows, modify saturation and deblurring. As you can see in the example below, it’s possible to increase details selectively such as in the raccoon’s fur by adjusting the detail size sliders.
|Original Image||Topaz Detail 2|