dcraw man page

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 [0-6]

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
6   ACES

-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

Referenced By

dcraw2hdrgen(1).

March 3, 2015