Wednesday, June 27, 2007
Double-Processing White Balance
Whether your goal is perfect neutrality or creating an effect, you can use this technique to refine the colors in your images
Process Twice And Layer
You can double-process a RAW file multiple times (classically twice, possibly more) and composite the various renditions, selecting or mixing specific image areas from each version. You can do this to neutralize areas with different light temperatures in images with mixed light sources, compensating for the tendency for digital capture to accentuate the differences. You can do this to accentuate differences in light temperature in an image; this can include both images with multiple artificial light sources and images with multiple natural light temperatures such as deep shade and full sun. You can do this to subjectively enhance light temperature between different regions of an image with little regard for accuracy, favoring expressive renditions instead. What you choose to do is a matter of intention; this may vary significantly from person to person or from image to image. How you choose to do it very likely will be the same.
Here's the process. Once the versions are processed, combine them in Adobe Photoshop.
1 Process the same file differently.
2 Open the various renditions of the file.
3 In the Layers palette, click, hold and drag the Background layer of one document into the window of the other document (the borders of the other window will become bold). These layers will automatically register because they have the same pixel count. In previous versions of Photoshop, you can hold the Shift key before dropping individual layers to ensure that this is true. Don't crop the files until after this composite is made; if you do, registering the separate layers will take time.
4 Add a Layer Mask. Use the mask icon in the Layers palette or select this option from the Layers menu.
5 To mask the areas of the layer above and reveal areas of the layer below, paint (with the Brush or Gradient tool) or select a channel (with the Marquee, Lasso, Magic Wand or Quick Mask), or load a channel as a selection and fill with black. Blend varying percentages of the renditions locally with shades of gray.
The final effect can be more or less naturalistic or expressive, depending on how you process and combine the multiple renditions of the file. Once you become comfortable with this technique, it's likely you'll discover many new possibilities contained in your images. In time, you'll begin making exposures with this technique in mind, finding possibilities in situations you previously might have overlooked. A new relationship with light awaits you.
A member of the Photoshop Hall of Fame, internationally renowned fine artist John Paul Caponigro is the author of Adobe Photoshop Master Class. He teaches an array of workshops in his private studio. Read reviews of ExpoImaging's ExpoDisc and GretagMacbeth's ColorChecker in Caponigro's free enews Insights and get over 50 free PDFs and test files at www.johnpaulcaponigro.com.
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