Re: purpose of DNG profile?
Re: purpose of DNG profile?
- Subject: Re: purpose of DNG profile?
- From: Andrew Rodney <email@hidden>
- Date: Wed, 08 May 2013 12:43:04 -0600
On May 8, 2013, at 11:57 AM, Tim Vitale <email@hidden> wrote:
> Is there someone on the list that knows the goal of the DNG profile?
Adobe raw processors use a DNG profile as part of the image processing chain. You can use the one's supplied for your camera type by Adobe, but your camera may not behave just like the sample used by Adobe to build the DNG profile. So create your own. I make one for Daylight + Tungsten then just for really odd illuminates (CFL, metal halide). Plus you may wish to edit the profile using the free DNG profile editor.
> Remember that the DNG profile was made with 'free software' after the purchase of a $100 target system. Yet another CC-24, added to a collection of CC-24s.
DNG profiles are created with a Macbeth 24 patch target. Anyone with such a target can build a profile for their cameras using two free software options (Adobe or X-rite).
The 24 patch Macbeth use in Adobe raw processors dates back many years, prior to DNG profiles and the work of the late great Bruce Fraser. He figured out a way to 'tweak' the calibration settings in early versions of ACR so that the ProPhoto processing space used in ACR would match what ProPhoto RGB of each 24 patch value should be out the back end. Then we got all kinds of scripts and finally Adobe enhanced the Calibration area with the ability to use custom DNG profiles.
> The problem described with color saturation seems to be a deal breaker for me.
DNG profiles shouldn't affect saturation this way per se. Images still need a decent ACR or LR default setting. Zero settings probably isn't it, certainly not with PV2010 or PV2003. If one see's an image with too much saturation, there are no less than three controls in the ACR engine to affect this. IF you see a saturation issue on many images, you simply alter, then update the ACR defaults.
>
> I had not noticed that the gamma was 'intentionally uncorrected,' only that it was NOT corrected.
>
> Coming from someone who always self-neutralizes the grays on the CC-24...
>
> THE GRAYS WERE NOT NEUTRALIZED! The second deal breaker.
Again, the idea of not White Balancing images by application of a DNG profile is faulty, the Adobe raw processing engine doesn't work that way. Many images will need a custom WB no matter the DNG profile, the two are separate. IOW, it isn't the role of a DNG profile to 'correct' WB. That's part of rendering the image.
In Adobe's way of processing raw, the idea is we are working with a negative, much as some of us did in the old analog dark room with color negs. The filter pack played a huge role in the color appearance. Nearly every neg needed a different filter pack recipe. The correct color is the color the printer desired, not necessarily the right color based on some measurement.
I've built a number of DNG Profiles for my cameras, I've yet to see a case where such a custom profile didn't produce a better appearing, more acceptable starting point for rendering then the supplied DNG profiles.
Andrew Rodney
http://www.digitaldog.net/
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