Does Rawtherapee support Vuescan Raw Tiff (DNG) format?
I can find discussion that rawtherapee was adapted to support scanning negatives via dslr in 2020 timeframe. In those discussions I find some discussion that work was on going to support regular scanner (non DSLR) for vuescan / silverfast.
I’m working with 40 year old 35mm slides.
It is a fact that I can produce via vuescan so called raw tiff files. These files are claimed to be gamma=1 files with .dng extension. IF I OPEN THESE FILES in rawtherapee, they look identical to the display presented by vuescan. If I use rawtherapee WB -Automatic and Refinement - Temperature Coorelation, I am able to use the two additional sliders AWB temperature bias and green refinement. All this looks like rawtherapee is supporting this format. However, if I use vuescan tiff dng files which are dng files with gamma set to 2.2, 1.8, or whatever depending on what vuescan color tab output color space is sRGB, adobe RGB, or proPhoto, this rawtherapee WB - Automatic and Refinement work but restricted in capability.
IF I take the vuescan rawtiff (gamma=1) dng file and feed it into Adobe Digital Format Converter, the converter produces new dng files with slight rawtherapee histagram changes. Feeding these adobe converted dng files into rawtherapee gets slightly better results (in my opinion) compared to vuescan dng output. The adobe documentations states that it is advised to run the converter on dng files since it will “normalize” older dng’s to the current standard. Seems to improve things a little bit.
It seems like rawtherapee is working with this workflow. Can it be said vuescan is supported?
I ask the question because it seems to work, there was prior mention (in 2020) that work was in progress, and the results seem ok.
Thank you for responding.
Which discussions are you referring to? Can you provide links? They might be specific to the film negative tool. As of 5.9, it supports non-raw images.
The temperature correlation white balance method has limited functionality for non-raw files. Does the raw tab show fewer tools with the non-linear (gamma ≠ 1) DNGs? That’s a good indicator that RawTherapee does not think the image is raw.
Yes - that’s right - within discussion of film negative tool.
Now it supports inversion just on the raw level, before demosaicing. It means you can invert just DSLR-scanned files; TIFFs/RAW DNGs from Silverfast/Vuescan are not supported. The tool’s author is working on it but it’s unavailable yet
Link
So on WB it looks like all is supported with nothing restricted. Also the raw tab has very limited support allowing white point to be set.
Also included are histagrams. The first was produced by so called vuescan rawDNG with gamma set to 1. I take that file and run it through the dng adobe converter. As you can see the histagram was modified by the converter. Adobe has comments that many DNG formats are in the world and that applying their converter on DNG files modifies the DNG into a more standard’s compliant format.
Everything looks right to me.
I don’t think the DNG converter modifies the image, but it could be replacing the embedded color profile with one that Adobe thinks is better.
Thanks for responding!
Does rawtherapee interpret the vuescan profile?
To display the profile using exiftool, I have to use the brute force method, namely exiftool -scanForXMP -b vuescan.dng.
For the adobe converted dng image I can use exiftool -xmp -b adobeConverted.dng. Use of -scanForXMP returns garbage on the converted image and I’m guessing adobe converter removed it.
xmp profile of adobe converted dng:
adobeConverted.txt (5.7 KB)
profile via brute force of vuescan.dng:
vuescan.txt (13.4 KB)
I’m not sure what you mean to say with the XMPs. If you are talking about the embedded color profiles, RawTherapee looks for the color matrices.
$ exiftool -ColorMatrix* -CalibrationIlluminant* picture.dng
Color Matrix 1 : 1.046890259 -0.5185089111 -0.08586120605 -0.3495941162 0.9834136963 0.4286651611 -0.0178527832 0.03730773926 0.6825866699
Color Matrix 2 : 0.9020843506 -0.2726135254 -0.1208190918 -0.3995361328 1.230117798 0.1880645752 -0.09811401367 0.1719970703 0.6538848877
Calibration Illuminant 1 : Standard Light A
Calibration Illuminant 2 : D65
