Re: [Gimp-user] Opening 16 bit SGI file

[Simon Budig <simon budig de>]

Michael Izquierdo via gimp-user-list (gimp-user-list gnome org) wrote:
> When I open a 16 bit SGI file, it is always converted to 8 bit sRGB. I
> convert it to 16 bit Linear Light and i can see the 16 bit RGB values, but
> it doesn't match the hex dat that I see in the SGI file. It's close, but
> not exactly the same.

It seems that the sgi plugin does not implement 16 bit loading at all,
so in the best case it drops the low byte for a start...

The SGI plugin creates an image using the babl format "R'G'B'A u8", so
it provides 8 bit data to the gimp that assumes the sRGB gamma curve.

When converting this to linear light (i.e. "no gamma" or gamma = 1) this
gamma curve gets compensated for, which shifts the values around, so it
is not really surprising that the values change.

I suspect to get proper support for your situation the first target
would be the file-sgi plugin. It needs to be extended to pass 16 bit (or
even higher?) values to the Gimp core in the first place. Probably not
that hard, but then - I have no clue at all about the sgi file format...

Bye,
        Simon

-- 
              simon budig de              http://simon.budig.de/