Adding AsShotNeutral and AsShotWhiteXY to DNGs produced by dng4ps-2

icameisaw

21

Adding AsShotNeutral and AsShotWhiteXY to DNGs produced by dng4ps-2

« on: 13 / June / 2020, 05:40:48 »

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After some years of wailing and gnashing of teeth about not being able to use the CRW files older versions of CHDK produced in the photo editing programs I have, I have finally used dng4ps-2 to convert them to DNG. (See other thread here for the settings used with for my old PowerShot S95.)

The good news is that programs can read them.

The bad news is that they then either fail to process them (DxO PhotoLab) or don't get the colours right (at least one Skylum program).

The problem is almost certainly that they're missing two things that dng_validate 1.5.1 says are legal not to include, but it's not recommended to omit them:

Code: [Select]

PS Z:\Shared\RAW> .\dng_validate.exe .\IMG_1070.DNG
Validating ".\IMG_1070.DNG"...
*** Warning: Neither AsShotNeutral nor AsShotWhiteXY included (legal but not recommended) ***
Raw image read time: 0.160 sec
Linearization time: 0.025 sec
Interpolate time: 0.164 sec
Validation complete
PS Z:\Shared\RAW>

Is there a way to add the info? I have the original JPGs for most of them.

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reyalp

14082

Re: Adding AsShotNeutral and AsShotWhiteXY to DNGs produced by dng4ps-2

« Reply #1 on: 13 / June / 2020, 12:44:27 »

Quote from: icameisaw on 13 / June / 2020, 05:40:48

Is there a way to add the info? I have the original JPGs for most of them.

I don't think there's a way to get the actual values the camera used. White balance is already applied in the jpeg data, so Canon doesn't record those values in the jpeg exif.

If you just need some value present, you could presumably add it with exiftool or similar (using, say, values from a CHDK DNG), but of course that won't give you correct white balance.

White balancing the image in your raw software is probably the best bet.

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icameisaw

21

Re: Adding AsShotNeutral and AsShotWhiteXY to DNGs produced by dng4ps-2

« Reply #2 on: 13 / June / 2020, 17:45:17 »

The problem with that is that the program with the best camera/lens correction (and noise reduction and..) is DxO's PhotoLab, and that won't read these

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reyalp

14082

Re: Adding AsShotNeutral and AsShotWhiteXY to DNGs produced by dng4ps-2

« Reply #3 on: 13 / June / 2020, 21:10:43 »

Quote from: icameisaw on 13 / June / 2020, 17:45:17

The problem with that is that the program with the best camera/lens correction (and noise reduction and..) is DxO's PhotoLab, and that won't read these

Adding a dummy AsShotNeutral should presumably allow you to load it, and then do whitebalance in DxO. I'm not familiar with DxO, but I assume any serious raw software lets set WB, either custom or presets like daylight etc.

I'd suggest values from the CHDK DNG with WB set to daylight as your dummy values, to ensure they are valid and reasonable enough to see what's going on.

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Don't forget what the H stands for.