dcraw(1) 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. Youll 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 cam- era clock was set to Universal Time.

-i Identify files but dont 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, typi- cally 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 dont 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 spec- ified 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 cameras 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 # dont 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), pnm- topng(1), gphoto2(1), cjpeg(1), djpeg(1)

AUTHOR Written by David Coffin, dcoffin a cybercom o net

May 14, 2009 dcraw(1)