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
-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, -M otherwise. 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 totally raw (no color scaling).
-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 cropping 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
May 14, 2009 dcraw(1)