[Digikam-users] Dark 16 bit RAW decoding

[Paul Waldo]

Thanks for the reply, Gerhard.

OK, this make a bit more sense now as to *why* UFRaw is working for me.  Any 
thoughts on why my profile, generated in lprof, causes the conversion to be 
very dark, almost black?

In case it helps, here is the output from lprof:

I have chosen CIE XYZ as PCS
Unknown white point (X:1e-314, Y:7e-312, Z:7e-312)
Primaries (x-y): [Red: 0.625415, 0.277302] [Green: 0, 1] [Blue: 0.0833993, 0]
Estimated gamma: [Red: 1.19788] [Green: 1.22472] [Blue: 1.24135]
Loading sheets...
Reference sheet: /home/paul/.lprof/target_refs/R060101.txt
Measurement sheet: /home/paul/.lprof/temp/meaurement.cgt
Gamut hull: 195 inside, 0 outside, 57 on boundaries
Fitting error (delta E CIELAB): mean=1.97997, RMS=3.01769, 95%%=6.1929, 
median=1.09214, MAD=0.666138
Fitting error (delta E CIE94): mean=1.10034, RMS=1.5087, 95%%=3.06707, 
median=0.777355, MAD=0.432199
Performing 2-fold cross validation ...
2-fold CV: estimated RMS dE=4.04654, dE94=2.04384
2-fold adj. CV: estimated RMS dE=3.70133, dE94=1.86485

Here are my profile parameters:

Resolution (CLUT points):  33
Profile verbosity: Store anything
Regression:
    Smoothness: 0.500
    Deviation: 1.00e-05
Linear Bradford 


On Friday 25 January 2008 12:03:20 pm Gerhard Kulzer wrote:
> Am Friday 25 January 2008 schrieb Paul Waldo:
> > I stumbled across a discussion of dark RAW conversions in the FAQ.
> > Apparently Digikam cannot use the manufacturer-supplied camera profile,
> > yet UFRaw can. This puzzles me, since they both are just front ends to
> > dcraw...
[snip]
>
> As I understand it, Canon profiles that come with the camera lack tone
> mapping and gamma correction parameters. digiKam does not touch these
> properties during raw conversion, but Ufraw does. They have a whole lot of
> code to supplement dcraw in the conversion process. One day dcraw will
> hopefully do it as it does it already for 8 bit, or we'll integrate the
> ufraw code.
>
> On the other hand Bibblepro and selfmade lprof profiles work well with
> digiKam in my experience since they have tone mapping included, images come
> out normally bright.
>
> Gerhard
>