[Digikam-users] burned zone in RAW file, but not in jpeg

[Remco Viëtor]

On Sunday 10 June 2012 21:52:06 Paul-Emmanuel GROFFE wrote:
> Hi all,
[...]
> Now my question: how come that some parts of a photo is burned (no data) 
> in a raw file, but is ok (not burned, with data) in the jpeg file (shoot 
> raw+jpeg, canon 450D camera) ? Isn't raw supposed to contain -more- 
> datas than jpeg  ?
> 

Hard to say anything without knowing what settings you use in the raw 
conversion tool in Digikam. My guess is that one or more of those mess up 
your conversion. So I'll just give a few ideas to check what happens.

For settings in the 'Raw Import' tool:

in the 'Raw decoding' tab, 'White Balance' section:
- make sure 'method' is set to 'Camera'
- use 'Highlights' -> 'Unclip' 
- uncheck all of the check boxes (especially don't use the exposure 
correction or make sure the sliders are at their default values)

Also, make sure that all options in the Post-processing tab are at their 
default values...

These settings should give you a basic conversion, with no brightness 
scaling, so you'll probably end up with a rather dark image. If you still 
get blown highlights from the raw file, you have a serious problem :)

And yes, theoretically, raw files contain more data than jpeg files (12/14 
bits vs. 8). But there are a lot of operations between the raw data and the 
final image, so lots of occasions to lose information

> Also, if you have some tips to get data back wihle in RAW I would 
> appreciate a lot.

There I have to disappoint you; no way to get data back that is lost in a 
previous step. You can prevent losing information though, by being careful 
in your treatment (using 16 bit/channel helps as well). Also, if one 
channel is over-exposed/blown in the highlights (usually giving a 'nice' 
magenta colour), there is an option that /might/ recover detail in those 
highlights: White Balance -> Highlights -> rebuild (try level 3 first). A 
faster way to get rid of the magenta colour is White Balance -> Highlights 
-> Solid white...

Remco
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