Color depth info

[Vadim34354904u44t]

Where can I check the colour depth of the imported file in Lightroom?

[Per Berntsen]

Set the Metadata panel to Default (top left), then click Customize at the bottom.

Check Bits per sample under Camera Info in the dialog that appears.

You can also rearrange the order of items in the panel by clicking Arrange at the bottom.

[Vadim34354904u44t]

Thanks a lot! The text line is there, but no information...

[Conrad_C]

I see that too, a blank Bits per Sample field. I wonder what the reason is. I tried a couple of raw files from different Sony cameras, and I get three different answers in three different applications. For example, for one camera I get…

Lightroom Classic: (Blank)

Adobe Bridge: 16 bits per pixel

RawDigger: 14 bits per pixel

The one that matches the manufacturer’s published spec for that camera is RawDigger, 14 bits per pixel.

Very odd…

[Per Berntsen]

I've never used this field before, but it does display bit depth for my DNG files, converted from RAF and NEF.

But it does not display anything for RAF and NEF files, and not for Tiff files either.

@Conrad_C  Does it display for any of your Sony cameras?

[Conrad_C]

Bits Per Sample is blank for all raw files from various current and old cameras in my catalog, six models across three different brands.

Bits Per Sample does report a value for DNG files.

Also, I noticed that Bits Per Sample is blank for HEIC files from the iPhone 15.

[John R Ellis]

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Bit depth is a huge tarball (like most everything else concerning metadata). I last investigated it two years ago:

https://www.lightroomqueen.com/community/threads/adobe-reports-16-bit-on-14-bit-gfx-100-shots.43767/... 

The Metadata panel field Bits Per Sample is the number of bits per sample for DNGs only (it appears in the panel's DNG tagset, and has the internal name "com.adobe.dng.bitsPerSample").  The field is supposed to represent the number of bits used by the camera sensor. LR computes DNG Bits Per Sample using the formula ceiling (log2 (WhiteLevel)), where WhiteLevel is a DNG parameter.

What Exiftool and Rawdigger (which uses Exiftool) report as Bits Per Sample for a raw or DNG is the number of bits used to store a sample in the file, not the number of sensor bits. Many cameras whose sensors are 12- or 14-bit use 16 bits to store samples in the file. I believe that for raw formats that use lossless compression, this is the number of bits per sample after uncompression.

LR has a smart-collection criterion Bits Per Channel that shouldn't be confused with DNG Bits Per Sample. It represents:

- For DNGs with mosaic (sensor) data, the number of sensor bits (that is, DNG Bits Per Sample).

- For raws, it always reports 16 bits, even if Exiftool shows a smaller value for Bits Per Sample (see the second screenshot below). (I've tested this with my sample catalog, which has 22 camera makes and 262 models.)

- For all other file types, the number of bits per channel used in the file. But for all the raws in my test catalog (22 camera makes, 262 models), Bits Per Sample is 16.

LR doesn't show Bits Per Channel in the Library Filter Metadata browser or in the Metadata panel. But last year Adobe finally exposed it to plugins. So (as you might guess) you can view it in the Filter command of the Any Filter plugin:

(Beware that LR 13.1 broke an important feature in the plugin SDK, and the Filter command will give lots of spurious errors, though eventually show you the right results. I'll be releasing workaround in the next day.)

Don't you miss the good ole days when companies paid experienced tech writers to maintain complete and accurate technical documentation?  (Yeah, and I walked to school 10 miles each way in winter blizzards.)

[Conrad_C]

What Exiftool and Rawdigger (which uses Exiftool) report as Bits Per Sample for a raw or DNG is the number of bits used to store a sample in the file, not the number of sensor bits. Many cameras whose sensors are 12- or 14-bit use 16 bits to store samples in the file. I believe that for raw formats that use lossless compression, this is the number of bits per sample after uncompression.

By @John R Ellis

Wow, thanks. That’s a very important distinction I needed to know!