Belmont 16 ft sailing club, photographic club

RECOVERING DETAIL FROM SHADOWS AND HIGHLIGHTS

[with the Shadow/Highlight adjustment]

This tutorial was prepared by Roy Killen and is copyright. It is part of the supplementary training materials for members of the Belmont 16 Ft Photographic Club and is not intended as a complete, stand-alone instruction package.

Comments and suggestions on this tutorial are welcome - they should be emailed to Roy Killen.

 

WHAT IS THE SHADOW/HIGHLIGHT ADJUSTMENT?

The Shadow/Highlight adjustment was introduced in Photoshop CS (version 8). It provides a very simple way to bring out detail in dark areas of an image (shadows) or in very light areas of an image (highlights). However, it is not magic! If you severely under-expose or over-expose an image you may clip the dark or light tones too much for them to be recovered by any means.

The results that can be achieved with the Shadow/Highlight adjustment can also be achieved in other ways that will be dealt with in other tutorials. In particular, you should try using the "Recovery" and "Fill Light" adjustments in Adobe Camera Raw if you have a RAW image. [Refer to this tutorial for details.]

As an example of what can be achieved with the Shadow/Highlight adjustment, compare the following two images:

The original is on the left. In the adjusted image on the right the shadows have been lightened dramatically and the highlights darkened slightly.

The adjusted image is far from perfect, but it illustrates the point that you can make fairly drastic changes to the tonal values of an image with the Shadow/Highlight adjustment. The following image shows a similar level of adjustment. In these two cases, the images have been improved to the point where they are now acceptable as "record" shots, but they are not prize-winners. For images (such as the two examples shown here) the Shadow/Highlight adjustment can make a difference, but it can't fully compensate for poor original exposure.

 

A more appropriate use of the Shadow/Highlight adjustment is to attempt to improve the overall tonal qualities of an image that originally has reasonable exposure. Such images can often be improved considerably by making subtle changes to the shadows and highlights as shown in the following example.

In the above image there is some lightening of the girl's hair and leg, and the bag. There is also some darkening of the light background so that it is less distracting.

It is always better to get the exposure as close to "correct" as possible in the original image. This is not always possible when there are very deep shadows or very bright highlights in the scene, or when you have to grab the shot quickly and you can't use fill-flash (as was the case with the above image). For these situations, it is worth keeping in mind that the Shadow/Highlight adjustment might be useful. So, let's look at how to use it.

 

USING THE SHADOW/HIGHLIGHT ADJUSTMENT IN PHOTOSHOP

The Shadow/Highlight command is found in the Image>Adjustments menu.

 

Unfortunately, you cannot make the Shadow/Highlight adjustment with an adjustment layer unless you first convert the image layer to a smart object. (Smart Objects will be dealt with in a later tutorial).

 

Since you cannot use an adjustment layer it is wise to duplicate your image layer and make the Shadow/Highlight adjustment on the duplicate layer. You will then be able to remove the Shadow/Highlight adjustment if you later decide it was not effective. You will also be able to use some of the properties of the layer (opacity and blend mode) to modify the effects of the Shadow/Highlight adjustmnet - see explanation below.

 

 
   

When you select Shadow/Highlight a dialogue box opens.

If you check the "Show More Options" box the dialogue box expands to a more detailed view.
   

Make sure you have the "Preview" box checked or you will not see the effects of the adjustments you make.

You will probably find that the default settings (shown here) give too much adjustment. You can change the defaults as follows:

(1) Set the sliders to values that you prefer to start with - from your experience.

(2) Click on the "Save As Defaults" button. Next time you open the Shadow/Highlight dialogue these new defaults will appear.

 

If you regularly use the Shadow/Highlight adjustment on particular types of images (such as sunsets where you want to lighten the foreground) you can save different sets of adjustments. All you need to do is make the adjustments on one image and then press "Save" - you will be asked to specify a location for saving the settings and to give the preset a name. When you want to use that setting again, just open the Shadow/Highlight dialogue and select "Load" - navigate your way to the location where you saved your preset and select it. You will now have a good starting point for adjusting your image.
 

The Shadow/Highlight adjustments are normally done in three stages - the shadows, the highlights and compensating adjustments. I find it best to start with the shadows as this is where you are most likely to see dramatic effects in most images. I always start with the Highlights Amount set to zero - so there will be no highlight adjustments and I can concentrate on the shadows.

The three sliders in the shadows part of the dialogue box have the following effects:

 

The amount slider determines how much the shadows are lightened. Its default value is 50% and you should try increasing and decreasing this value to suit the image you are working with because there is no "best" value for all images.

The tonal width slider determines which tones in the image are affected by the Amount slider. If you use a low Tonal Width number only the darkest tones will be lightened. A higher number will cause the adjustments to extend into the mid-tones.

The radius slider determines how much information Photoshop takes into account when making the adjustments. Pixels are lightened (or darkened) according to the average brightness of the surrounding pixels. If the Radius slider is set to zero or a very low amount, Photoshop has very little information to work with when trying to calculate the average luminance values of the pixels in the areas surrounding the adjustment. The result will probably be a rather "flat" image in which you lose detail in the lightened areas. If the Radius value is set too high, the lightening effect (of a Shadows adjustment) will spread all over the image rather than being confined to the darkest areas. For high resolution images, you will probably find a Radius of 30-100 is a good starting point. The final "best" value will vary for each image.

 

When you are happy with the shadows adjustments it is time to adjust the highlights. The three sliders operate in the same fashion as they did for the shadows adjustments - except now you are trying to bring back detail in the bright areas of the image.

Next, you can make any colour corrections that are necessary. Brightening the shadows and darkening the highlights will sometimes exaggerate any colour that was present in those areas - giving unwanted colour saturation. You can try to compensate for this by moving the Colour Correction slider to the left. This will affect only the changed parts of the image. Of course, some images will benefit from increased colour in the adjusted areas and you can achieve this by moving the Colour Correction slider to the right

Finally, you can fine tune the contrast in the areas of the image that have not been altered by the shadows and highlights adjustments by moving the Midtone Contrast slider.

 

 

WHAT MIGHT GO WRONG?

  1. If you make very severe adjustments to the shadows you might bring out unwanted noise in these areas. [See example below.] If this happens, try reducing the amount of shadows adjustment.
  2. Lightening the dark areas of an image can reduce the overall contrast too much. To compensate, try increasing the Black Clip value - this determines the range of tones that are forced to be pure black.
  3. If you take the highlights adjustments too far, then the image may start to look dull because objects that are supposed to be very bright (e.g. reflections from shiny objects) will no longer be pure white. You can compensate for this with the White Clip setting at the bottom of the Shadow/Highlight dialogue box. The figure in the White Clip box determines what range of tones are forced to be pure white.
  4. Changing the Black Clip and White Clip points is a fairly severe way of preserving black and white in your image. You may have more success if you leave the Black Clip and White Clip levels at their default values, make the Shadow/Highlight adjustments as described above, then add a Curves adjustment layer with a moderate "S-curve" to restore the desired level of contrast.
  5. If you take the Radius slider too far to the right you might notice a soft halo appearing in areas of sharp contrast between light and dark areas of the image. On some images you can reduce this effect with the 'fade" command - see below.

THERE IS A LIMIT

The Shadow/Highlight adjustment can help to improve some images, but there is a limit to how much detail can be recovered. The following example illustrates that if you try to recover detail from very deep shadow (in a greatly under-exposed image) you may simple produce a very noisy image.

sunset
 

REFINING THE SHADOW/HIGHLIGHT ADJUSTMENTS

If you make your Shadow/Highlight adjustments in a duplicate layer this allows you to refine them in two ways:

  • First, you can reduce the opacity of this layer (using the slider in the Layers palette) to produce a more subtle change.
  • Second, you can use a layer mask to restrict the Shadow/Highlight adjustments to selected parts of the image.

An alternative way of refining the Shadow/Highlight adjustment is to use the "fade" command. After you complete the adjustment, select Edit>Fade Shadow/Highlight. In the dialogue box that appears you can adjust the "opacity" of the effect and the "blend mode". This is similar to the above suggestion of performing the Shadow/Highlight adjustment on a duplicate layer.

 

MONOCHROME IMAGES

The Shadow/Highlight command can be used with monochrome images. However, in the expanded dialogue box the "Colour Correction" slider changes to a "Brightness" slider.

For most images, you will probably find that it is best to make all your adjustments (including Shadow/Highlight) on the colour image and then convert it to monochrome. If you are using Photoshop CS3 or CS4 you will find that the "Black and White" conversion option (Image>Adjustments>Black and White) will give you a lot of control over the shadow and highlight areas of the image.

 

A DIFFERENT APPROACH

If you are working with RAW image files then you may find that you get better results trying to recover shadow and highlight detail in Adobe Camera Raw (or a similar program). To explore this option, refer to this tutorial.

 

 

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This page last updated 13th September 2009 (RK)