Tuesday, February 17, 2009
Aesthetics Of XDR
Using Extended Dynamic Range techniques judiciously will keep you from taking a good thing too far
You have many choices before you. Experimentation sensitizes you to possibilities. Ultimately, you’ll make your own informed decisions. As with solving any problem, it’s easier if you break it down into its component pieces and then learn what each one does and how they interact with one another. First, know what to look for. Second, know what a tool can do. Third, know how to apply a tool. Once you’ve done this, you’ll be well along the way to crafting a unique style that’s all your own. Master musicians choose from a host of possibilities (tools, techniques and applications) to craft a distinctive style. Visual artists do the same.
While you need to make bracketed exposures and merge them to preserve shadow and highlight detail (a true HDR image), you can work with a single exposure and still achieve a heavily postprocessed HDR appearance (a faux HDR image). In a few situations, this can be useful for both the classicist and the pioneer.
How is this useful for photographers interested in simulating a classic look? HDR processing options enable you to accentuate texture. In images or areas of images that are relatively low contrast but contain subtle texture, that texture can be accentuated dramatically. Here’s just one example. Skies with relatively little apparent texture or contrast can suddenly become much more interesting, even dramatic.
2) LDR image with heavily simulated HDR effects using Photomatix
• Pronounced shadow and highlight detail
• Accentuated edge contrast E Accentuated texture
• Increased noise
• Smoothed texture
• Saturation distortions
One of the easiest ways to generate the look of aggressive HDR processing is to use HDR software, such as Photomatix (www.hdrsoft.com), to process your Low Dynamic Range images. Simply duplicate your file. With two identical sources, you can access the tone-mapping functions contained in the software.
Make a duplicate of your file. Open Photomatix and click Generate HDR, selecting both the original and the duplicate, and then click OK. Under Exposure Value Setting, specify any E.V. spacing and click OK. Under Generate HDR—Options, use the default settings and click OK. Click Tone Mapping and use the sliders in Details Enhancer. When you’ve achieved a look you like, click Process. Here’s a whirlwind tour of the Photomatix interface.
• Use Light Smoothing and Strength to control halos. Highlights Smoothing also can provide some control
• Use Shadows Smoothing and Highlights Smoothing to control shadow and highlight detail.
• Use Micro-contrast and Micro-smoothing to control the accentuation or reduction of texture and noise.
• Use Saturation Shadows and Saturation Highlights to distort saturation relationships. (Use Saturation to increase or reduce global saturation.)
You can localize any HDR effects by combining them with an LDR image. First, process a file normally. Second, process a file with HDR software. Open both files. Drag and drop the HDR layer onto the LDR layer. Add a mask to the top layer and paint away the effect selectively with a black brush.
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