dcraw(1)

NAME
dcraw - command-line decoder for raw digital photos

SYNOPSIS
dcraw [OPTION]... [FILE]...

DESCRIPTION
dcraw decodes raw photos, displays metadata, and extracts thumbnails.

GENERAL OPTIONS

-v  Print verbose messages, not just warnings and errors.

-c  Write decoded images or thumbnails to standard output.

-e  Extract the camera-generated thumbnail, not the raw image. You'll get either a JPEG or a PPM file, depending on the camera.

-z  Change the access and modification times of an AVI, JPEG, TIFF or raw file to when the photo was taken, assuming that the camera clock was set to Universal Time.

-i  Identify files but don't decode them. Exit status is 0 if dcraw can decode the last file, 1 if it can't. -i -v shows metadata.

    dcraw cannot decode JPEG files!!

REPAIR OPTIONS

-I  Read the raw pixels from standard input in CPU byte order with no header. Use dcraw -E -4 to get the raw pixel values.

-P deadpixels.txt
    Read the dead pixel list from this file instead of ".badpixels". See FILES for a description of the format.

-K darkframe.pgm
    Subtract a dark frame from the raw data. To generate a dark frame, shoot a raw photo with no light and do dcraw -D -4 -j -t 0.

-k darkness
    When shadows appear foggy, you need to raise the darkness level. To measure this, apply pamsumm -mean to the dark frame generated above.

-S saturation
    When highlights appear pink, you need to lower the saturation level. To measure this, take a picture of something shiny and do dcraw -D -4 -j -c photo.raw | pamsumm -max

    The default darkness and saturation are usually correct.

-n noise_threshold
    Use wavelets to erase noise while preserving real detail. The best threshold should be somewhere between 100 and 1000.

-C red_mag blue_mag
    Enlarge the raw red and blue layers by the given factors, typically 0.999 to 1.001, to correct chromatic aberration.

-H 0
    Clip all highlights to solid white (default).

-H 1
    Leave highlights unclipped in various shades of pink.

-H 2
    Blend clipped and unclipped values together for a gradual fade to white.

-H 3+
    Reconstruct highlights. Low numbers favor whites; high numbers favor colors. Try -H 5 as a compromise. If that's not good enough, do -H 9, cut out the non-white highlights, and paste them into an image generated with -H 3.

COLOR OPTIONS
By default, dcraw uses a fixed white balance based on a color chart illuminated with a standard D65 lamp.

-w  Use the white balance specified by the camera. If this is not found, print a warning and use another method.

-a  Calculate the white balance by averaging the entire image.

-A left top width height
    Calculate the white balance by averaging a rectangular area. First do dcraw -j -t 0 and select an area of neutral grey color.

-r mul0 mul1 mul2 mul3
    Specify your own raw white balance. These multipliers can be cut and pasted from the output of dcraw -v.

+M or -M
    Use (or don't use) any color matrix from the camera metadata. The default is +M if -w is set or the photo is in DNG format, -M otherwise. Besides DNG, this option only affects Olympus, Leaf, and Phase One cameras.

-o [0-5]
    Select the output colorspace when the -p option is not used: 0 Raw color (unique to each camera)
    1 sRGB D65 (default)
    2 Adobe RGB (1998) D65
    3 Wide Gamut RGB D65
    4 Kodak ProPhoto RGB D65
    5 XYZ

-p camera.icm [ -o output.icm ]
    Use ICC profiles to define the camera's raw colorspace and the desired output colorspace (sRGB by default).

-p embed
    Use the ICC profile embedded in the raw photo.

INTERPOLATION OPTIONS

-d  Show the raw data as a grayscale image with no interpolation. Good for photographing black-and-white documents.

-D  Same as -d, but with the original unscaled pixel values.

-E  Same as -D, but masked pixels are not cropped.

-h  Output a half-size color image. Twice as fast as -q 0.

-q 0
    Use high-speed, low-quality bilinear interpolation.

-q 1
    Use Variable Number of Gradients (VNG) interpolation.

-q 2
    Use Patterned Pixel Grouping (PPG) interpolation.

-q 3
    Use Adaptive Homogeneity-Directed (AHD) interpolation.

-f  Interpolate RGB as four colors. Use this if the output shows false 2x2 meshes with VNG or mazes with AHD.

-m number_of_passes
    After interpolation, clean up color artifacts by repeatedly applying a 3x3 median filter to the R-G and B-G channels.

OUTPUT OPTIONS
By default, dcraw writes PGM/PPM/PAM with 8-bit samples, a BT.709 gamma curve, a histogram-based white level, and no metadata.

-W  Use a fixed white level, ignoring the image histogram.

-b brightness
    Divide the white level by this number, 1.0 by default.

-g power toe_slope
    Set the gamma curve, by default BT.709 (-g 2.222 4.5). If you prefer sRGB gamma, use -g 2.4 12.92. For a simple power curve, set the toe slope to zero.

-6  Write sixteen bits per sample instead of eight.

-4  Linear 16-bit, same as -6 -W -g 1 1.

-T  Write TIFF with metadata instead of PGM/PPM/PAM.

-t [0-7,90,180,270]
    Flip the output image. By default, dcraw applies the flip specified by the camera. -t 0 disables all flipping.

-j  For Fuji Super CCD cameras, show the image tilted 45 degrees. For cameras with non-square pixels, do not stretch the image to its correct aspect ratio. In any case, this option guarantees that each output pixel corresponds to one raw pixel.

-s [0..N-1] or -s all
    If a file contains N raw images, choose one or "all" to decode. For example, Fuji Super CCD SR cameras generate a second image underexposed four stops to show detail in the highlights.

FILES

./.badpixels, ../.badpixels, ../../.badpixels, ...
    List of your camera's dead pixels, so that dcraw can interpolate around them. Each line specifies the column, row, and UNIX time of death for one pixel. For example:

     962   91 1028350000  # died between August 1 and 4, 2002
    1285 1067 0           # don't know when this pixel died

    These coordinates are before any stretching or rotation, so use dcraw -j -t 0 to locate dead pixels.

SEE ALSO
pgm(5), ppm(5), pam(5), pamsumm(1), pnmgamma(1), pnmtotiff(1), pnmtopng(1), gphoto2(1), cjpeg(1), djpeg(1)

AUTHOR
Written by David Coffin, dcoffin a cybercom o net