Nikon D40 NEF/RAW images with Linux

Caveat: I’m not too much into photography so everything I posted here might be wrong. It’s just my opinion as an end-user.

I’ve bought myself a Nikon D40 some time ago and finally had enough spare time to shoot some images and post-process them. My environment of choice is Ubuntu Linux so the obvious image management/edit tools were gimp and f-spot.

An first attempt did show some strange behaviour: f-spot did display NEF/RAW images quite different than gimp. It seems as if the (gimp) NEF import step did something to the white-balance and gamma so that imported images did look worse. The worst thing is: while f-spot does display beautiful images it is not able to export them to a more sharable format as JPEG.

GIMP is using ufraw to convert the NEF images, after playing with its parameters I’ve discovered that using a downloaded color profile for the D40 and some custom Gamma and Continuity values does provice a near approximation of the f-spot results. The used values are:

Gamma	0.4
Continuity	0.01-0.04
ICC	got it here
White-Balance	use camera

A drawback of using ufraw is it’s slow processing speed. Interestingly using ufraw-batch on the command line does not exhibit this problem, so just use:

ufraw-batch --gamma 0.4 --contuinity 0.02 --wb=camera *.NEF

While not being a problem at all, this is something that should work out-of-the-box, ie. the user should not be irritated by photos being displayed differently between applications.

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