DavidMXG's photostream

Mainly interested in landscape photography.


For image processing I use:
-- GIMP - picture editor
-- UFRaw - to process raw files
-- Qtpfsgui - for tone mapping & HDR work
-- IrfanView picture browser may run on Linux using Wine

All these run on Linux & Windows - & are open source & free, except IrfanView which is only free. Generally I find the Linux operating system better to use than Windows, irrespective of the cost of Windows.

An advantage of UFRaw is that it may be used as a GIMP plug-in, such that UFRaw may be used to adjust the picture using the full bit depth the camera raw file provides, by adjusting the graph. So if your final image is only 8 bit, you still had the full bit depth available in the camera raw file (12 bit or more) where it counts - expanding the tones using UFRaw in major initial adjustments direct on the raw file data at camera bit depth. Fine adjustments (or sometimes extreme adjustments) may be done in the GIMP afterwards.

dcraw is a program to convert camera raw files into standard image formats (whatever the operating system). It is open source & is used by many open source programs, & some others, such as the merely free IrfanView.
dcraw may also, if you are inclined that way, be used at the command line on its own, see dcraw manual.
The source of dcraw is
www.cybercom.net/~dcoffin/dcraw/dcraw.c
which I successfully compiled on Linux by,
"gcc -o dcraw -O4 dcraw.c -lm -DNO_JPEG -DNO_LCMS"
The executable runs, typing "./dcraw" provides help. So, after putting a link to the executable in the system path, I worked on a Nikon raw file trying various settings, thus:

command ...................................................................# result

dcraw -w -o1 -T -H 0 -k 50 -b 2 dsc_0059.nef # good, slightly greenish, but that might be the original due to leaves.

dcraw -o1 -T -H 0 -k 50 -b 2 dsc_0059.nef # good, no reference to camera white balance.

dcraw -a -o1 -T -H 0 -k 50 -b 2 dsc_0059.nef # reasonable, auto white balance, but too much green in this image.

dcraw -o1 -T -H 0 -k 50 -b 1.5 dsc_0059.nef # reduced brightness to keep grey of sky, very natural.

dcraw -w -o1 -T -H 0 -k 40 -b 1.5 dsc_0059.nef # good -- camera-white-balance -w; darkness-level -k; brightness -b

-H :: 3 or 1 too dark; 2 (blend) is good ; 0 (clip) sky may be over-bright for this combination.

dcraw -w -o1 -T -H 2 -k 40 -b 1.5 dsc_0059.nef
dcraw -w -o1 -T -H 0 -k 40 -b 1.5 dsc_0059.nef # these good, though 0 bit too bright, so, larger k extends black -

dcraw -w -o1 -T -H 0 -k 45 -b 1.5 dsc_0059.nef # good, back level good

dcraw -w -o1 -T -H 2 -k 45 -b 1.5 dsc_0059.nef # about right - but not as good as I would get with graphic control to custom adjust colour, saturation & adjust curve to increase separation of low tonal values using UFRaw &/or GIMP.

dcraw -o2 -T -H 2 -k 45 -b 1.5 dsc_0059.nef # BEST -- slightly red but natural-looking white balance for this early-evening summer picture.

-h (half-size) is useful for quick testing.

However to get the tones right I find a graph is most useful, so the gradient may be adjusted manually at each point of the light levels.

________________________________________
en.wikipedia.org/wiki/GIMP
www.gimp.org/
portableapps.com/apps/graphics_pictures/gimp_portable
ufraw.sourceforge.net/
qtpfsgui.sourceforge.net/
www.irfanview.com/
www.linux.org/
www.winehq.org/
www.cybercom.net/~dcoffin/dcraw/