Tuesday, August 10, 2010
RAW Workflow Basics
Taking full control of your images is easy when you know how to work in RAW
Labels: Image Processing How To
Capturing digital photos in RAW mode provides a variety of benefits, such as the ability to fine-tune color temperature after capture, greater exposure latitude than JPEG capture and the opportunity to work with high-bit data. Despite these benefits, many photographers opt for JPEG capture because RAW is perceived as being overly complicated. The truth is, the latest software tools make a RAW workflow easy. The key is to become familiar with the basics so you’ll be able to process your RAW image files with confidence. In most cases, working with RAW is simply a matter of opening it in your image-optimization software. This will enable you to access a wide variety of controls for optimizing the image in the conversion process.
Optimize Color Temperature
While digital cameras generally do a good job of evaluating the color of light illuminating a subject and compensating to give accurate color, sometimes you’ll need to provide a little bit of help. Most RAW conversion software provides preset options that mimic those found on your digital camera such as Daylight, Cloudy and Tungsten. That’s a good start, but you can achieve a better result with a manual adjustment. This is accomplished primarily with a Temperature adjustment that allows you to shift the color of your image between blue and yellow. Think of this adjustment as being both corrective and creative, and make an adjustment that produces the most pleasing result. You also may have a Tint slider available that provides a shift between green and magenta, and is more corrective in nature generally (and, therefore, calls for a modest adjustment).
Maximize Tonal Range
Maximizing the distribution of tonal values in the RAW conversion will help ensure you have the maximum amount of information and detail in the image as you begin optimizing the resulting image. This involves adjusting the white and black points for the image so the brightest pixels are rendered nearly white and the darkest pixels are rendered near black. If you’re using Adobe Camera Raw, you can hold the Alt/Option key while adjusting Exposure and Blacks to enable the clipping preview display that shows where detail is being lost. Adjust both sliders to the point just before you start to lose detail. You also can focus your attention on the histogram display, adjusting the white and black points until the histogram stretches to the full width available without getting “cut off” at the edge of the display. Keep in mind that while most images will benefit from tonal range expansion, for scenes with particularly low contrast, you should prioritize the appearance of the image rather than the histogram.
Fine-Tune Overall Tonality
While the key priority is maximizing tonal range, it’s also helpful to produce a converted image that will require the minimum adjustments to look its best. The Color Temperature adjustments help ensure the color is optimized, but you may need additional refinements for the overall tonality. Stick to the Brightness adjustment that will allow you to optimize the overall tonality without undoing the tonal range expansion you’ve already applied. It’s best to avoid other adjustments for contrast, as those likely will serve to adversely affect the previous maximization of tonal range.
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