Surely the best thing to do is to just shoot normally, expose properly and, if the Nikon base curve is excessively boosting highlights, use a different curve. I certainly wouldn't want to go around underexposing my shots just to suit a particular raw development tool whether this is dt or not.
You might try one of the Pentax curves I use, they don't seem to ever cause this problem for me. I assume that the Nikon curve was constructed to mimic as far as possible the appearance of jpegs straight out of the camera and that involved some sort of bright tone lift. If you aren't worried about 'exact' match of jpeg and 'out of the box' processed raw files there seems nothing wrong with just using a curve that doesn't have effects you don't want. Rgds, Rob. -----Original Message----- From: Chris Siebenmann [mailto:c...@cs.toronto.edu] Sent: 06 June 2013 17:18 To: David Vincent-Jones Cc: darktable-users@lists.sourceforge.net Subject: Re: [Darktable-users] Best way to recover highlights that are blown in processing? | Something that I now find that is more effective is the use of the | channel-mixer along with blentif. I also am using the lightness tab to | select the brightest pixels and then I pull the red values slightly | back which gives the blue values a chance to be seen. | | I have however become a lot more cognicent of the problem during the | shooting session in an effort not to have to deal with this situation | later on. As far as I can see the only real way to deal with this during the shooting session is to underexpose significantly[*], unless I'm missing something. The current state of affairs really seems to be that bright but unclipped highlights will be shoved into over-exposure by darktable's base curves (and sometimes other processing); to avoid this you must avoid bright highlights in the RAW, ergo underexposure. (It is easy enough to see this happen by turning on overexposure markers and then flipping back and forth in the initial history stack between 'sharpen' and 'base curve'. The difference in my sample NEF is quite striking.) If I had a suitable step wedge test chart, I would actually do the experiment to find the first stop of highlights that darktable's Nikon base curves push into blown highlights. Someone familiar with the code and the base curves wouldn't even need to do any tests. My guess is that the important thing to know is the L level that is effectively blown; base curves themselves are relatively readable in src/iop/basecurve.c. - cks [*: here I mean 'underexpose well beyond the point needed to avoid hard clipping'.] ------------------------------------------------------------------------------ How ServiceNow helps IT people transform IT departments: 1. A cloud service to automate IT design, transition and operations 2. Dashboards that offer high-level views of enterprise services 3. 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