Camera Raw CS3: Highlight Recovery and Fill Light
Having stayed relatively the same for the last couple of releases, Camera Raw users had likely grown used to the standard Exposure, Shadows, Brightness and Contrast sliders to control lighting when adjusting raw images. As of Photoshop CS3 though, Shadows has been renamed to Blacks, and Adobe has added two new sliders labeled Recovery and Fill Light. This week, we'll take a look at these new controls.
Before we do though, Adobe has also changed the way you enable highlight and shadow clipping display. Rather than checking boxes above the image preview area as in past versions, you now have to click on the small icons in the upper corners of the histogram. The one we'll need here is for display of highlight clipping and is located naturally enough above the highlight end of the histogram. Except for specular highlights and some reflections from metal or similar objects, clipped highlights just look wrong. Getting rid of them is almost mandatory. There's a similar shadow clipping icon button above the shadow end of the histogram that allows you to see where your shadows are being clipped, but I generally don't find it as useful as I do the highlight clipping option. Shadows are expected in nature and retaining at least some of them in an image can actually improve an image by making it more dramatic.
Once you turn on highlight clipping, you may notice that some areas of your image turn into ugly, bright red splotches. These are the areas being clipped. In earlier versions of Camera Raw, the usual way to deal with them was to lower the Exposure slider to get rid of them which affected the entire image, sometimes enough to be a real problem. Being forced to choose between a well exposed image with burned out highlights or an image underexposed enough to get right of those clipped highlights rendered some raw images all but unusable. You could lessen the problem by converting to ProPhoto RGB, a color space with a gamut wide enough to contain at least some of those clipped highlights, but would only work up to a point.
The Recovery slider in the latest release of Camera Raw provides a better option. By default, it's set all the way to the left so that it is essentially turned off. As you slide it towards the right, it progressively begins to affect the clipped highlights in the image you are working on by modifying the tone curve only at the highlight end. You can see its effect not only in the image but also in the histogram as you raise its setting. There is a surprising amount of detail present in the clipped highlight areas of many images that can be restored by a judicious use of Recovery. Camera Raw has always been good at restoring highlight detail so long as at least one channel wasn't clipped, but now the Recovery slider gives us a way to get it to do so without adversely affecting the rest of an image.
Fill Light is another wonderful addition to Camera Raw and attempts to perform a similar kind of magic for restoring shadow detail. In areas where one or two channels have clipped shadows, Camera Raw can reconstruct the clipped channels based on what exists in channels that are not clipped. Increasing the setting of the Fill Light slider allows you to digitally shine a light on such areas and bring out detail that would otherwise be obscured without affecting areas that should be black based on the Blacks slider (what used to be the Shadows slider). Consider it at least somewhat akin to moving the midpoint slider in Levels such that more of the image becomes above medium gray.
Bright red areas showing clipping in Camera Raw 4.2.
Notice that the histogram is clipped, particularly
on the highlights as would be expected from the image.
The improved image after adding a touch of Recovery and FIll Light.
Notice that the histogram looks better now too.
Both Recovery and Fill Light can be overdone of course. Raise Fill Light too much and you will begin to see fringing between the affected areas and adjacent black areas that remain unaffected. The same is true for Recovery. Only so much detail can be recovered and if you attempt to push things beyond that you will only create harsh edges between the burned out white that remains and the now improved areas where you have recovered highlight detail. Sometimes, there's just no substitute for doing things right in the field when you shoot a series of images. Digital darkroom techniques can definitely make a good image better, but a bad image generally remains just that: a bad image.
Adobe has made some major improvements to Camera Raw as of the release of Photoshop CS3. It's like the experience with Lightroom taught them some new tricks and they were eager to teach them to Photoshop users too. I'm not a Lightroom user, but I do appreciate what it's done for the rest of us.