Man page for dcraw Copyright (c) 2015 by David Coffin You may distribute without restriction. David Coffin dcoffin a cybercom o net http://www.cybercom.net/~dcoffin
NAMEdcraw - command-line decoder for raw digital photos
SYNOPSISdcraw [OPTION]... [FILE]...
DESCRIPTIONdcraw decodes raw photos, displays metadata, and extracts thumbnails.
- Print verbose messages, not just warnings and errors.
- Write decoded images or thumbnails to standard output.
- Extract the camera-generated thumbnail, not the raw image. You'll get either a JPEG or a PPM file, depending on the camera.
- 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.
- 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!!
- 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 OPTIONSBy default, dcraw uses a fixed white balance based on a color chart illuminated with a standard D65 lamp.
- Use the white balance specified by the camera. If this is not found, print a warning and use another method.
- 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
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
- -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.
- Show the raw data as a grayscale image with no interpolation. Good for photographing black-and-white documents.
- Same as -d, but with the original unscaled pixel values.
- Same as -D, but masked pixels are not cropped.
- 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.
- 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 OPTIONSBy default, dcraw writes PGM/PPM/PAM with 8-bit samples, a BT.709 gamma curve, a histogram-based white level, and no metadata.
- 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.
- Write sixteen bits per sample instead of eight.
- Linear 16-bit, same as -6 -W -g 1 1.
- 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.
- 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.
- :./.badpixels, ../.badpixels, ../../.badpixels, ...
List of your camera's dead pixels, so that
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.