[Digikam-users] Raw converter: no exif, only 8bit

[Guillaume Castagnino]

Le Sat, 19 May 2007 12:42:44 +0200, Martin Schmettow a écrit:

> Hi,

Hi,


> after I got the svn version running, I tried the raw converter and
> experienced two problems:
> 1) Although in settings the output format is set to tiff 16bit I can
> just get 8bit. This can't even be set in the Raw Image Converter Dialog.
> 2) none of the metadata of the raw image (NEF) is exported to tiff.

the raw converter is a kipi-plugin, not the digikam raw part. And yes, 
this kipi-plugin is only 8bit at the moment.
To use the digikam raw feature, you simply have to "edit" (F4 by default) 
your picture. This way of handling your raw file will honor the settings 
of raw decoding you entered in digikam setup. The kipi-plugin way will 
not, since it will use it's own configuration.


> When I open the nef directly in the Editor and save it to tiff, this
> yields 16bit. However, the image appears much to dark in the editor.
> Raising the Gamma to 2 yields nearly the same impression than in the
> preview. Wouldn't that be better a default. Or is there some reason not
> to adjust anything, when a raw is opened directly?

Having your RAW dark is a normal thing in 16bit mode. RAW are basically 
decoded as linear. But to get something like your jpg preview, you need 
to apply a non-linear transformation : you need to apply a color profile.
For example, a quite standard working profile is sRGB. sRGB is a gamma 
2.2 space (near the gamma of the eyes).
But gamma 2.2 should NEVER been applied by default, since it depends on 
the working profile you want to work in.

If you want to have directly a good-looking picture, use 8bit mode ;)

You can find some informations of such color-profile and gamma management 
all around the web. For example : http://www.aim-dtp.net/aim/calibration/
srgb/g_spaces_srgb.htm
You will find many others in google ;)


Regards,
Guillaume



-- 
cdlt,
Guillaume Castagnino