Lightroom Classic: Strange white balance for overlayed NEF

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  • Updated 2 months ago
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Many Nikon DSLR's have an overlay function which combines (overlays) two NEF images to produce a third NEF image in-camera. The source images don't have to be different, so an image can be combined with itself, which is what I did for this example.

I have noticed that for such combined images, the WB for As Shot has Temp: 2880 and Tint: -119, regardless of the WB camera setting of the original images. In this example, I shot an image with my D750's WB set to Daylight. Importing the original image into Lr Classic 8.0 gives the As Shot WB as Temp: 5300 Tint: +7, which is always the value for this WB setting. See the screen-shot below:



If I change the WB from As Shot to Daylight, the values change slightly to Temp: 5500 Tint: +10, as shown:



Combining this image with itself using 0.5 for the contribution of both source images to make a new overlayed NEF and importing into Lr, in develop I see this:



White balance for the image looks fine, but the settings aren't right for the WB camera setting. Changing the WB from As Shot to Daylight shows how incorrect Lr has got the WB:



For comparison, Nikon's Capture NX-D gives the 'As Shot' WB settings Temp: 5209 Tint: 0 for both the original and the combined (overlayed) images. Changing settings to Direct Sunlight changes Temp: 5200 Tint: 0 in both cases without drastically changing the images' appearance.

The overlay camera function takes its settings from the first image selected for the overlay. So if overlaying two different images that were shot with different WB settings, the combined image has the WB settings for the first image. Capture NX-D reflects this - first image Daylight, second image Shade, the combined image has Temp: 5209 Tint: 0. First image Shade, second image Daylight, the combined image has Temp: 8006 Tint: 0. For Lr, either combined image has Temp: 2880 Tint: -119.
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Anthony Blackett

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Posted 11 months ago

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Anthony Blackett

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This post seems to have gone unnoticed by everyone!
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Anthony Blackett

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Lr Classic 8.4 and 9 months later, this problem still hasn't been fixed, let alone being acknowledged. Extremely disappointed in Adobe's inability to fix bugs reported by its users.

A correction to my original post is that the default Temp is set to 2800, not 2880.

My understanding is that Lr evaluates its own WB value because it can't use Nikon's propriety methods. So how can Lr get this so wrong?

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Pavan Kumar, Employee

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Hello Anthony, I tried to reproduce this issue but don't have a D750 right now, so used a D800. I shot an image with manual exposure and WB set to daylight. Then overlay - same image in both the sections with 0.5 values in both and saved the image. Imported the single image and overlay image as well, and in both of them WB was 5,050 and +8. Changing it to daylight in LR set it to 5500. Please let us know if there are any other steps that you used or if that was all.

It would be great if you could share the raw file where this happens too. Thanks!
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Anthony Blackett

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Hello Pavan, I have added two images to Dropbox for you to test. The original, DSC_0387.NEF was shot with camera WB set to daylight and aperture preferred exposure. The second image, DSC_0388.NEF is the overlayed image created in the same way you described, i.e. selected the original in both sections with 0.5 settings and saved.

In Lightroom Classic 8.4, after import the original image DSC_0387.NEF has an initial WB 'As Shot' Temp: 5300 Tint: +7 and when I change the WB setting to 'Daylight', I get Temp: 5500 Tint: +10 and the image still looks normal.

After import, the overlayed image, DSC_0388.NEF, has an initial WB 'As Shot' Temp: 2800 Tint: -119. Changing the WB setting in Lr to 'Daylight' gives the same as with the original image, Temp: 5500 Tint: +10, but the image has a horrible pink cast. Using the White Balance Selector will return the image to normal appearance when a 'grey point' is sampled, but the Temp and Tint are still wildly wrong. For example, zooming in on the beach in the image and sampling the darkest part of the sand gives me Temp: 2950 Tint: -128.

Files are here:

https://www.dropbox.com/sh/xpy0gcm0or5sypg/AAAYL5b-xMKpvhnfLaP41Dx7a?dl=0

Let me know if there is any problem downloading the files. I hope this helps.

Tony





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Pavan Kumar, Employee

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Thanks for the files Tony! I did try it and yes, the WB shows as 2800 and -119. Does that happen with all files or only this particular one? 
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Anthony Blackett

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Hello Pavan,

This happens with all files, and also regardless of the original's WB setting.

Tony
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Anthony Blackett

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Hello Pavan,

I've been looking into this a bit further and found that opening the overlayed image in RawTherapee gave much the same result. This made me think the problem is in the NEF, not in Lightroom. Checking the EXIF metadata I see that WB_RBLevels is "1 1 1 1" in the overlay image, but is "1.94921875 1.34375 1 1" in the original file.

My conclusion is that the D750 overlay function is applying a WB correction to each NEF file's data before combining them. This makes a bit of sense to me so that it can handle two images shot with different WB settings. It is a pity that the overlay function doesn't check to see if the two images have the same WB setting and then combine them without changing the red/blue values.

Tony