Saturday, 14 July 2012

Extreme contrast edits in Lightroom 4 and ACR 7 | By Martin Evening | source: www.dpreview.com


With the launch of Lightroom 4, Adobe formally introduced a new version of the raw processing engine that powers both Lightroom and Photoshop's Adobe Camera Raw (ACR) 7 plug-in. Known as Process Version (PV) 2012, it represents quite a radical shake up in the way you can now process your Raw (and non-Raw) images.

The new PV 2012 controls offer the ability to create an HDR-ike tonal range from a single image capture.
Adobe has offered several reasons for this change. With earlier process versions - PV 2003 and PV 2010 - there was a degree of overlap between some of the Basic panel tone controls, not to mention confusion among users as to the most effective slider combinations.
In addition, the default tone settings differed for Raw and non-Raw images. Different amounts of adjustments were therefore required depending on whether you were editing a Raw image or a JPEG for example, making it problematic to share settings between the two file types. So on one level PV 2012 is an attempt to make tonal adjustments more straightforward and intuitive to perform.
Above all though, the range of control when editing raw images was becoming somewhat limited by what the PV 2010 (and earlier) adjustment sliders would allow. The sensor performance of today's mirrorless and DSLR cameras make it possible to effectively extract a more extended dynamic range. The thing is, you need the raw processing tools to keep up with these developments. PV 2012 is Adobe's effort to do just that. In this article, we'll compare some of the raw file editing capabilities of PV 2012 against its predecessor, PV 2010.

What's changed in the PV 2012 Basic panel?

In PV 2012, there are still six primary tonal adjustment sliders in the Basic panel, all intended to be used in their order of appearance. But some sliders have been replaced and those that remain have seen changes in functionality. It's important to note that, unlike previous versions, most of the PV 2012 controls are scene adaptive, meaning their behavior - even at default settings - is optimized on a per image basis.
Here you can see PV 2010's
default tonal adjustment
settings for raw files.
In PV 2012, the default
value for each tonal
adjustment slider is 0 for
both raw and non-raw files.
The Exposure slider is effectively a combination of PV 2010's Exposure and Brightness sliders. It is used set overall image brightness. The Contrast slider is now scene-dependent, offsetting its operational midpoint slightly depending on whether you are editing a low key or high key image. 
Brand new Highlights and Shadows sliders offer separate luminance control for midtone-to-highlight and midtone-to-shadow regions, respectively (although there is a degree of overlap between the two). They work in both positive and negative directions and on an evenly balanced scale. So you can lighten or darken the highlights and shadow areas independently, with a +10 move being similar in strength to a -10 adjustment. The Whites and Blacks sliders are used to adjust the end points for the image's brightest and darkest tones, respectively.

Controlling a high contrast image with PV 2012

In the examples below, we'll take a look at the benefits PV 2012 offers over its predecessor when working on a high contrast raw image that contains a wide dynamic range. Here I'll be using ACR 7, which provides the same PV 2012 adjustments as Lightroom 4.
I shot this image from inside the entrance of a church building. This photo was captured in RAW mode and contains just about enough information in the highlight and shadow areas to show the complete tonal range. The challenge of course is how to process the image to extract this information.
In the image above you can see by the histogram I've overlaid that the highlights are blown out and the shadow details are completely hidden. Because this is a Raw file, however, we can extract some data that would have simply been lost in an 8-bit JPEG.
With a little patience it is possible to recover some highlight and shadow detail using PV 2010. I began by reducing Exposure by nearly 1 stop, to -.95 in an effort to minimize highlight clipping. I set both the Recovery and Fill Light sliders to their maximum values - an extreme move - in order to restore even more detail in the highlights and open up the shadows. The Blacks slider was then increased from its default of +5 to +13 in an effort to regain some of the contrast lost by my extreme Fill Light adjustment. I then lowered Brightness to +40 (from its default of +50) and increased Contrast to +50 (from its default of +25).
While the PV 2010 edits are certainly an improvement over the original image, we are left with a somewhat flat looking image with muddy shadows and relatively little contrast in the background areas of the scene. And you'd be hard pressed, too, to argue that the slider adjustments I've described above are intuitive. Let's take another pass at the same file, but this time using PV 2012.
Using PV 2012 controls I was able to increase Exposure to +45 to brighten the overall  image. I also increased Contrast to +36. I used an extreme Highlights adjustment of -100 to eliminate clipping in the clouds and a +100 Shadows adjustment to bring out more detail in the interior shadows. Note that by eliminating highlight and shadow clipping I was then able to actually boost my white point by setting the Whites slider to +10 and lower my black point by moving the Blacks slider to -35. These last steps allowed me retain much more image contrast, which I then increased a bit more throughout the midtone range with a Clarity slider adjustment of +7.
As you can see, the PV 2012 options give me greater control over the tones in the image in a more straightforward, though by by no means dumbed-down manner. In the crops that follow you can see just how much difference there is in using PV 2012 versus PV 2010.
PV 2010 default settingsPV 2012 default settings
Notice how much more shadow detail is visible in PV 2012's default settings. This initial rendering obviously provides a better starting point for extracting useful information.
PV 2010 after editingPV 2012 after editing
At first glance the edited results may look very similar. But take a closer look at these crops (click on the thumbnails for a larger view) and you'll see that the PV 2010 image shows distinct halos around the column edges as well as false color in the clouds. Overall, the PV 2012 image offers a much more natural, 'less-processed' looking result.

Enhancing a low contrast image with PV 2012

I just showed you some of the advantages to using PV 2012's Basic panel controls in compressing the tones in a very high contrast scene. Well, here is an example of how you can do the opposite and expand the tones more effectively in PV 2012. In the following examples I'll be using Lightroom 4. These same adjustment sliders are also available in ACR 7.
This photograph of Eliean Donnan Castle in Scotland was taken in pouring rain, using a telephoto lens. The primary editing task here is to increase contrast.
With a low contrast image like the one above, the easiest way to increase contrast is often to make the shadow regions darker. Doing that in PV 2010, however, usually involves two separate steps, as I'll demonstrate below.
PV 2010 default raw file settings.To produce the image shown
below, I moved the Blacks
slider to 53.
Working in PV 2010, here is the result after applying a Blacks adjustment of 53 in order to set a relatively high black clipping point and thereby enhance the contrast. Adjusting the Blacks slider certainly helps to pin down the deepest blacks, but in doing so, the shadow detail has become 'clogged up'.
In the image above, the darkest tones in the image have been set to maximum black. Overall contrast is improved, but the effect here is a bit overdone, with too much shadow detail missing. I then used the Fill Light slider to open up the shadow regions; a reduction in contrast for the sake of more image detail.
I used a Fill Light adjustment of 19 to bring out more detail in the shadows I created in the previous editing step.
PV 2010 often requires adjusting both the Blacks and Fill Light sliders in tandem to find a successful combination that allows you to clip the shadows and retain detail in the deepest shadows.
Still in PV 2010, here is the result of adding a Fill Light adjustment of 19 to regain shadow details that were lost by the aggressive Blacks slider setting in the previous edit.
The image above has increased contrast compared to the original image and contains more shadow detail than the previous edit. Yet in PV 2010, the Blacks slider has a 'knock on' effect, boosting saturation. The green trees and foliage look a bit unnatural in this context.
Let's compare this with the revamped Blacks slider available in PV 2012. Due in part to its adaptive nature as well as to the existence of a separate Shadows slider, the Blacks slider in PV 2012 makes it much simpler to set the clipping point without losing excessive shadow detail.
 PV 2012 default settings.I moved the Blacks slider to
a value of -51.
Here is the result of using a single adjustment in PV 2012; moving the Blacks slider to -51.
As you can see, setting the black clipping point is a one step process in PV 2012. All you have to do is adjust the Blacks slider and you are done. You can of course make further adjustments to the other sliders in order to achieve the desired result, but the new Blacks slider on its own does not have the same 'knock on' effect we saw in PV 2010.

Conclusion

We've just seen how the changes in PV 2012 can provide you with better results than its predecessor in more extreme editing situations. Spend some time using it in Lightroom 4 and/or ACR 7, and I think you'll quickly find that PV 2012 offers benefits with less extreme images as well. I do encourage you, however, to experiment specifically with images of very high contrast. Where I once used Photomatix or Merge to HDR Pro to blend exposure-bracketed images together, I am finding that using just a single median exposure image and PV 2012 adjustments like those I've shown you here, I can often get similar, if not better results.

Martin Evening is an award winning advertising and fashion photographer based in London, England. He is also a best-selling author of instructional titles such as The Adobe Photoshop Lightroom 4 Book andAdobe Photoshop CS5 for Photographers.