Chapter 4: camera raw, Introduction to camera raw, About camera raw files – Adobe Photoshop CS4 User Manual
Page 86: About camera raw, And apply postcrop vignettes to images. see, Camera raw
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Last updated 1/10/2010
Chapter 4: Camera Raw
Introduction to Camera Raw
About camera raw files
A camera raw file contains unprocessed, uncompressed grayscale picture data from a digital camera’s image sensor,
along with information about how the image was captured (metadata). Photoshop Camera Raw software interprets the
camera raw file, using information about the camera and the image’s metadata to construct and process a color image.
Think of a camera raw file as your photo negative. You can reprocess the file at any time, achieving the results that you
want by making adjustments for white balance, tonal range, contrast, color saturation, and sharpening. When you
adjust a camera raw image, the original camera raw data is preserved. Adjustments are stored as metadata in an
accompanying sidecar file, in a database, or in the file itself (in the case of DNG format).
When you shoot JPEG files with your camera, the camera automatically processes the JPEG file to enhance and
compress the image. You generally have little control over how this processing occurs. Shooting camera raw images
with your camera gives you greater control than shooting JPEG images, because camera raw does not lock you into
processing done by your camera. You can still edit JPEG and TIFF images in Camera Raw, but you will be editing pixels
that were already processed by the camera. Camera raw files always contain the original, unprocessed pixels from the
camera.
To shoot camera raw images, you must set your camera to save files in its own camera raw file format.
Note: The Photoshop Raw format (.raw) is a file format for transferring images between applications and computer
platforms. Don’t confuse Photoshop raw with camera raw file formats. File extensions for camera raw files vary
depending on the camera manufacturer.
Digital cameras capture and store camera raw data with a linear tone response curve (gamma 1.0). Both film and the
human eye have a nonlinear, logarithmic response to light (gamma greater than
2). An unprocessed camera raw image
viewed as a grayscale image would seem very dark, because what appears twice as bright to the photosensor and
computer seems less than twice as bright to the human eye.
For a list of supported cameras and for more information about Camera Raw, see
.
For a list of supported cameras that require Camera Raw 5.0 or higher, see
About Camera Raw
Camera Raw software is included as a plug-in with Adobe After Effects® and Adobe Photoshop, and also adds
functionality to Adobe Bridge. Camera Raw gives each of these applications the ability to import and work with camera
raw files. You can also use Camera Raw to work with JPEG and TIFF files.
Note: Camera Raw supports images up to 65,000 pixels long or wide and up to 512 megapixels. Camera Raw converts
CMYK images to RGB upon opening. For a list of supported cameras, see
.
You must have Photoshop or After Effects installed to open files in the Camera Raw dialog box from Adobe Bridge.
However, if Photoshop or After Effects is not installed, you can still preview the images and see their metadata in
Adobe Bridge. If another application is associated with the image file type, it’s possible to open the file in that
application from Adobe Bridge.