Today’s Question: I often begin optimizing an image by lowering the Highlights a bit, to eliminate any red “warning pixels” that Lightroom [or Adobe Camera Raw] might show me where I risk losing detail in the highlighted areas.
As I proceed, I may increase the Clarity a bit, to improve contrast and sharpness. But this often brings back the red warning pixels. (I think it may also bring back the blue warnings for loss of detail in the dark areas, but I’m inclined to worry less about that.)
Why does increasing Clarity result in possible loss of detail in the highlight areas?
Tim’s Quick Answer: Increasing the value for Clarity in Adobe Camera Raw or in Lightroom’s Develop module increases contrast, which can most certainly cause a loss of some detail in the brightest highlights or the darkest shadows in a photo. After increasing the value for Clarity, it is a good idea to check the values for the Whites and Blacks sliders (or simply view the clipping preview display) to determine whether detail has been lost, in which case you can adjust the values for Whites and Blacks to recover that lost detail. The same is also true for other adjustment controls, including the Highlights and Shadows adjustments, for example.
More Detail: The Clarity adjustment is, of course, a rather sophisticated adjustment. While the emphasis of this adjustment is to improve detail, that detail is improved by adding contrast within the photo. I think of this as an “intelligent” contrast enhancement, because it is applying an effect similar to sharpening to emphasize detail for the mid-tones in the image without having a significant negative impact on the highlights or shadows.
However, even with the sophisticated approach employed by Clarity, the additional contrast can cause some degree of detail loss in the highlights and shadows.
Especially if you have applied a relatively strong increase for the Clarity adjustment, it can be important to revisit the values for Whites and Blacks. In the question presented here, the clipping preview displays for shadows and highlights had been enabled, causing a red overlay on the image to indicate where highlights have been clipped and a blue overlay to indicate where shadows have been clipped. This option can be enabled by clicking on the triangle at the top-left (for shadows) and top-right (for highlights) of the histogram display on the right panel in both Lightroom and Adobe Camera Raw. You can also hold the Alt key on Windows or the Option key on Macintosh to enable a clipping preview while adjusting the Whites and Blacks (among other adjustment controls).
My general approach to applying basic tonal adjustments is to first set the white point by adjusting the Whites slider value with the aid of the clipping preview display. I then adjust the Blacks slider value, again with the clipping preview display. I’ll then fine-tune the overall detail and contrast using the Highlights and Shadows sliders.
At this point I will apply a Clarity adjustment based on an evaluation of the image. However, I will then revisit the Whites and Blacks values to ensure the peak values are still set appropriately.
In my view, it is always a good idea to revisit the Whites and Blacks values toward the end of your workflow for optimizing an image, especially for images where you want the brightest and darkest pixels to be near the white or black limit. The Clarity adjustment can cause an increase in contrast that causes a degree of clipping of highlights and shadows. The Highlights and Shadows sliders can also cause clipping.
So the point is, while we might generally think of the Whites and Blacks sliders as establishing the brightest and darkest values in a photo, other adjustment controls can also impact those pixel values. It can therefore be important to go back and forth between the various adjustments that relate to overall tonal values in the photo, to make sure you’re achieving the results you intend for the photo.