Sunday, December 5, 2010

Section 6 - Digital Processing

          Chapter 6 discusses what happens after the image is taken in the field. It talks about filling up a 1-2 GB storage card such as a compact flash. The author recommends using multiple small capacity cards in case of a disaster which causes the loss of all images on the card. It also recommends backing the images up on both a hard drive and a computer in case the images are lost from one of the places. More battery power allows the photographer to look through the images and delete the ones that are poorly exposed, leaving more room for photos in the field.
          RAW mode is the mode used exclusively by most professional digital photographers. RAW saves all of the data in its original state with no processing of the image done by the camera. No sharpening, color changes or tweaking of contrast are done in this format. These images must be turned into a TIFF or PSD to work with them on a computer. The author recommends Photoshop CS for most digital cameras.
          The original RAW image when first opened looks dull an unsharp. The chapter goes on to discuss how this can be fixed using Photoshop. They first suggest making changes using adjustment layers that can be turned on and off. The recommended first adjustment is to the brightness. Usually it is only a small change unless there was something that stood out on the histogram. The author says to use common features as a reference because they take up a large portion of the composition. The next adjustments are done with the levels scale which changes certain tonal ranges such as the whites and blacks. The next step given is to adjust the color saturation. This can be done to all of the colors at the same time or by choosing only red or green and so on.
          Contrast refers to the difference between the colors in an image. A scene with high contrast has a very large difference between the brightest brights and the darkest darks. Usually adjustments are made to allow for as much color recording as possible while retaining an original that is similar in appearance to the scene as seen while the photo was shot. The histogram can give an idea of high contrast if there are gaps in it. These gaps show lack of color information in that tone. Different contrast adjustments include a standard overall adjustment and a shadows/highlights adjustment and a midtone contrast adjustment.
          Other adjustments are more specific to certain parts of an image. There is a digital version that allows for dodging and burning. Other tools highlight certain regions that can be adjusted individually. The next step is to retouch things such as telephone wires, garbage, and other unwanted options from the compositon. One way to do this is using the healing brush. This tool takes pixels from one par that was selected to the part that needs some touching up. It matches automaticalls in light and texture. The other way to do this is the clone stamp, which is similar but not automatically modified in light and texture.

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