[Digikam-users] Questions on RAW conversion: Base curve

[Gilles Caulier]

2013/9/11 Elle Stone <l.elle.stone at gmail.com>:
> In the digikam raw processing WB section there is "autobrightness"
> which sets the white level (Gilles, yes?), which is not the same as
> white balance. From the dcraw
> manpage,http://www.cybercom.net/~dcoffin/dcraw/dcraw.1.html

This settings is in WB section because is a post demosaicing
operation, and it's color relevant.

It apply a curve to image. See below.

>
> COLOR OPTIONS
> By default, dcraw uses a fixed white balance based on a color chart
> illuminated with a standard D65 lamp.
>
> -w Use the white balance specified by the camera. If this is not
> found, print a warning and use another method.
> -a Calculate the white balance by averaging the entire image.
> -A left top width height Calculate the white balance by averaging a
> rectangular area. First do dcraw -j -t 0 and select an area of neutral
> grey color.
> -r mul0 mul1 mul2 mul3 Specify your own raw white balance. These
> multipliers can be cut and pasted from the output of dcraw -v.
>
> OUTPUT OPTIONS
> By default, dcraw writes PGM/PPM/PAM with 8-bit samples, a BT.709
> gamma curve, a histogram-based white level, and no metadata.


^^^^ Auto-brightness is here, extended to 16 bits color depth...

It analyse histogram and compute a gamma curve automatically.

Gilles Caulier