It can be loads of fun taking pictures, but the resulting images can be disappointing. We are lucky we live in the digital age: computer software can now rescue those disappointing images–and even improve the keepers. Once the images have been taken and processed, they can be optimized for monitor display and integrated into a slide mxl tv. In this article, I will discuss my work flow for slide show development. This will include the following:
Although there are other programs with many of the same features, I use Adobe Photoshop CS2 for my image processing. All of my images are captured in the Camera Raw format. Using this format, I can adjust things like exposure before I open the image in Photoshop for normal processing–while preserving the original image data at all times. A good book on Adobe’s Camera Raw is Real World Camera Raw with Adobe Photoshop CS2 by Bruce Fraser.
Camera Raw also allows me to take advantage of special techniques, such as Luminance Masking, which can help preserve detail in shadows and highlights that might otherwise be lost. Once the image processing is done, I use WnSoft’s PicturesToExe to create the slide shows and, as a side benefit, screen savers.
Why do these problem show up in images? If you are like me, sometimes you just want to point-and-shoot. I do not always fuss with camera settings–or sometimes I just forget a critical camera setting. For instance, overexposure can usually be avoided by setting the camera to underexpose images by -1/3 to -1 stop: if this is done, detail in bright highlights are not likely to be lost. The camera’s exposure compensation is adjusted to do this. Do I always do this? Nope! That is one reason I need a program like Photoshop. Unfortunately, once highlight detail exceeds the dynamic range of the camera, the detail is lost forever.
What can be done in this situation? Appropriate sky background from another image can be used to replace a blown-out sky. Pasting in replacement background is also a good corrective solution to eliminate a flash reflection. I do alter my images in this way, when necessary, to make them more closely resemble the scene as I actually experienced it. However, on my web site, I make it clear that I do so.
Exceeding the dynamic range of the camera’s sensor can also cause posterization effects. In order to cure this problem, the affected areas can be treated with a dose of saturation and/or hue adjustment.
In low light situations, when I do not use a tripod, I do the best I can with an externally-mounted flash unit. Even so, distant image detail is sometimes shrouded in darkness. Fortunately, the shroud can usually be lifted using Photoshop’s Shadow/Highlight adjustments. Lifting image detail out of the shadows can be particularly rewarding–and is made easy in Photoshop.
To correct lens distortion problems, Photoshop has a couple of great tools: the Lens Correction filter and the Free Transform command. With these tools, camera lens distortions can be corrected, and crooked horizon lines can also be corrected.
Other Photoshop tools, such as the Clone Stamp and Spot Healing tools can be used to correct problems such as the dust spots caused by a dirty lens.
As suggested above, some image problems are due to the high contrast of the scenes we want to capture. Where the dynamic range of the scene is likely to cause loss of detail in either the highlights or shadows, a digital darkroom technique called “Luminance Masking” can be used to help preserve this detail.
Luminance Masking can tame a high-contrast scene and help reduce loss of highlight and shadow detail. This technique works with images saved as RAW images (.CRW files). Briefly, the technique is analogous to taking two images: one image is exposed for the highlights and another for the shadows. The images are then combined in the digital darkroom to take advantage of the best of both.
After image selection and correcting image problems, I look at each image and decide how I’ll use it in the slides show. Generally, I like an image to be a full screen image for the show. Since I design my shows for a 1024 x 768 pixel screen resolution, I will sometimes crop to this size before spending a lot of time correcting image problems in parts of the original image that won’t be seen in the slide show. At other times, especially when the image is a portrait (taller than wide) rather than a landscape (wider than tall) and I want to use the entire image, I need to enlarge the canvas so that I can crop out a 1024 x 768 pixel slide.
