[ptx] Adobe DNG format SDK

[Kai-Uwe Behrmann]

Am 24.04.06, 23:24 +0100 schrieb Bruno Postle:

> On Tue 25-Apr-2006 at 00:01 +0200, Kai-Uwe Behrmann wrote:
> > Am 24.04.06, 21:23 +0100 schrieb Bruno Postle:
> > 
> > > Apparently 16bit integer data isn't considered 'HDR', most
> > > applications that manipulate 16bit files just treat them as finer
> > > grained versions of 8bit data - These tools will generally do the
> > > wrong thing with the 16bit linear data as produced by dcraw (as they
> > > would with linear 8bit data).
> > 
> > You can specify a gamma for dcraw. The newer dcraw version has a good
> > white/blackpoint behaviour. Images look bright out of dcraw. Just colour
> > saturation has to been handled. 
> 
> That is kind-of what I meant, the linear 16bit output from dcraw isn't handled
> very well by tools such as cinepaint or hugin.
> 
> The 16bit workflow that makes sense is to create gamma corrected output from
> dcraw and work with this in hugin/cinepaint exactly as you would with 8bit
> data.
> 
> All this is completely different to working with 'real' HDR floating-point
> high dynamic range data - Something I haven't managed yet.

What are the problems, you meet with linear HDR's?

When you create a HDR in CinePaint, <image> > File > New From > Bracketing 
to HDR, and load your (currently 8-bit downgraded) images into the 
plug-in, you have various curves inside. Try to make the Response Curve a 
straight line and play with the resulting HDR.
I did not find something strange or difficult about it. If you need a sRGB 
with gamma 1.0, I can create one and send to you.

For 16-bit linear images (or just raw's), perhaps there are not 
many tools, which handle carefully enough. Most algorithms expect gamma 
applied image data.

regards
Kai-Uwe Behrmann
                                + development for color management 
                                + imaging / panoramas
                                + email: ku.b at gmx.de
                                + http://www.behrmann.name