Most photographers have produced images that are less than perfect when viewed on a computer screen, even though they may have looked pretty good when displayed on the camera’s monitor. But there are also times when you can see straight away that a shot won’t turn out as you wanted, and make adjustments to prevent the more serious problems.
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Most photographers have produced images that are less than perfect when viewed on a computer screen, even though they may have looked pretty good when displayed on the camera’s monitor. But there are also times when you can see straight away that a shot won’t turn out as you wanted, and make adjustments to prevent the more serious problems. In this feature we’ll look at the most common lighting-related errors. In most cases, correct exposure will enable you to avoid them. But sometimes, the only way to correct them is with editing software. 1. Blown-out Highlights: You know this problem has occurred when the brightest areas in a shot ‘blow out’ to stark white with no details in them. Unfortunately, there’s no way to put back information that wasn’t recorded in the first place so this is one situation where preventive measures are vital. If your camera includes a dynamic range adjustment setting, use it. This is the most effective ‘fix’ for this problem. Otherwise, expose for the highlights, using the on-screen histogram as outlined in the Insider article on page 40.  A correctly-exposed shot of a scene in which the brightness range exceeds the sensor’s dynamic range. No detail is recorded in the brightest highlights.
 An enlargement of the blown-out area shows that no amount of brightness and contrast adjustment can put in highlight details that weren’t captured in the first place. Partially-recorded areas are also posterised. The Editing Fixes: There’s nothing you can do to restore missing information, although you can recover over-exposed areas where some detail has been recorded. Reduce the contrast by a couple of steps. Use the Shadows/Highlights adjustment tool in your image editor. If you’ve shot raw files and converted them into 16-bit TIFF files, you have a better chance of recovering some image detail in over-exposed areas. When working with JPEG files, take care not to produce a ‘posterised’ result showing a dramatically reduced tonal range through excessive adjustment. 2. Blocked-up Shadows: When the subject looks too dark or is partially silhouetted against a correctly-exposed background, more light is needed to ‘open out’ the dark areas. Close subjects can benefit from flash fill, which brightens up the shadows. You may need to set the flash output to between -0.3 and -1.0EV to achieve a natural looking result. Scenic shots require correction at the editing stage.  In this backlit shot, the foreground would be improved if it was lightened, although the sky is correctly exposed. We, therefore, want to brighten the former while leaving the latter unchanged. The Editing Fixes: For maximum control and the lowest risk of posterisation, use one of the selection tools to select the area you wish to brighten. Feather the edges by between 10 and 20 pixels (depending on the size of the image file) to avoid visible boundaries between the areas you will work on and those that remain unchanged.  Selecting the area for a brightening layer. Then right-click on the selected area – or click on the Layers tab in the toolbar – and select Layer via Copy. Adjust the Brightness and Contrast sliders in the Adjustment or Enhance sub-menu until you achieve the result you want. Local fine-tuning can be achieved with the Dodge tool. 
| An alternative method is to use the Shadows/Highlights adjustment tool to balance out both ends of the tonal scale. However, there is a risk of posterisation if large changes in either shadows or highlights is required.  Using the Shadows/Highlights adjustment tool.  An example of posterisation caused by excessive adjustment to brighten shadowed areas with the Shadows/Highlights adjustment tool. The original shot is on the left, while the adjusted image is on the right. 3. Flat-looking Pictures: This problem is usually inherent in the subject itself and there are plenty of ways to correct it (including in-camera contrast adjustments). However, you usually obtain better results at the editing stage where you have more tools at your fingertips and greater control over adjustments.  Misty scenes can make attractive subjects but often look flat and uninteresting when shot. The Editing Fixes: Simply selecting the Auto Levels or Auto Tone adjustment might provide all the correction you need. If you use Photoshop, you can control the intensity of the adjustment by selecting Edit > Fade Auto Tone and adjusting the slider in the pop-up window. These controls can be handy when the default adjustment is too strong.  The Auto Levels adjustment in Photoshop Elements provides a quick and easy way to improve flat-looking images.  When editing in Photoshop, you can fine-tune the intensity of the Auto Tone (and also Auto Contrast and Auto Colour) adjustment. 4. Colour Casts: If you’ve photographed a subject under indoor lighting there’s a good chance of it having a colour cast. Incandescent lighting is particularly difficult for most cameras’ auto white balance controls to correct and many manual pre-sets over-correct. The Editing Fix: You can usually achieve natural looking colours with the Auto Colour correction tool in your image editor.  Incandescent lighting can add a warm cast to shots that is difficult for the camera’s auto white balance controls to correct. 
The Auto Colour correction tool provides a simple way to remove most colour casts.
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