DCRaw Reference

Here’s an excerpt from DCRaw’s man page (Retrieved: October 30, 2007).

-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!!
-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.
-n noise_threshold
	Use wavelets to erase noise while preserving real detail. The best threshold should be somewhere between 100 and 1000.
-b brightness	By default, dcraw writes 8-bit PGM/PPM/PAM with a BT.709 gamma curve and a 99th-percentile white point. If the result is too light or too dark, -b lets you adjust it. Default is 1.0.
-4	Write 16-bit linear pseudo-PGM/PPM/PAM with no gamma curve, no white point, and no -b option.
-T	Write TIFF output (with metadata) instead of PGM/PPM/PAM.
-k black	Set the black point. Default depends on the camera.

-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.

-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.

no white balance option

Use a fixed white balance based on a color chart illuminated with a standard D65 lamp.

+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.

-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 3-9

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.

-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.

-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.

-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.

-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.