Q: Color space: Adobe RGB or sRGB, does it matter for raw files?

Started Jun 4, 2012 | Discussions thread
AK83
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Re: Q: Color space: Adobe RGB or sRGB, does it matter for raw files?
In reply to j_photo, 1 month ago

j_photo wrote:

So out of curiosity, I just shot the same scene twice, once with the camera color space set to sRGB (top histogram below) and once set to Adobe RGB (bottom histogram). I set EC to -1, to give space at the right side to see what was happening to highlights.

I don't see any difference in highlights. At the left ends, the sRGB image has more areas in darker shadow and some fully blocked areas. Picture control was Neutral.

I'm not sure what if any conclusions to draw. Just thought some might be interested to see. Comments are welcome.

sRGB histogram above, Adobe RGB histogram below

Hi j_photo,

Just to clarify a few things about colourspace settings.

As most others have already said, the colourspace setting makes no difference on the raw file data itself.

it does however make a difference in the raw image.

By that I mean, because you are using Nikon software, the way Nikon software works(CNX2 here) ... it doesn't render the raw data directly as an image, it creates a tiff file and you subsequently do all your edits(in CNX2) on this tiff file.

When you save, it obviously saves that edit data to the raw file.

The tiff file is a throwaway file.

If you want to see this tiff file directly, it will be stored in whatever location on your hard drives, you have set the CNX2 cache to be.

The files themselves are a bit cryptic, in that they are simply a string of alphanumeric characters only .. no file extension.

An example file name may be: 1234567890ABCDEFGHIJKLMNOPQRSTUV

If you change the extension of this file to .. 1234567890ABCDEFGHIJKLMNOPQRSTUV.tif, you can use any tif capable software to open, view or edit this file as you please.

Note that some software display the two pages that this tif file contains.

So technically, this idea that it doesn't matter what colourspace you set your camera to shoot in .. is slightly incorrect.

It may matter what colourspace you choose to use.

But with Nikon software, in 99.99999% of situations it doesn't.

You set colourspace as you please on the raw file, but noting that the raw file you assume that you are seeing is not a raw file, but a raster file(in this case, tif).

Another point to be mindful of when 'setting colourspace'(quotation marks deliberate!!) ... doing so is also setting the colourspace on the embedded jpg preview files.

It won't make much difference in real terms, but if you choose to use any raw file software that uses the embedded jpg preview files to render the raw file image, then this can have an impact.

Note that as you edit an NEF in CNX2, and let say you change the colourspace from sRGB to aRGB(or even ProPhoto, if you have the profile installed and registered!!) .. you could potentially screw up the way the raw file may be rendered by some software that uses the embedded jpg preview file to render the preview file.

eg. of this type of software are: FSViewer, Nikon's own VNX2(I don't use VNX-i), even Windows Explorer(file explorer, not IE!!).

I don't have access to Apple devices, so can't comment on their file explorer.

If you have Nikon's NEF codec installed and then use Windows file explorer to quickly browse through images, in some rare situations, messing about too much with colourspace settings could impact on the way the NEF file is previewed.

As an example of why I changed to sRGB colourspace setting in camera:

A while back I needed a way to quickly create some jpg files of my raw files, as they were on the camera.

I was shooting in aRGB at that time(thought there was some supposed advantage!)

I used a small program to extract the jpg files from the raw files once downloaded to the computer(IJFR .. InstantJpgFromRaw).

Great little program that allows you to quickly make some jpg files  in mere seconds.

That is, these jpg files are not rendered, or converted, simply extracted from the raw file. I'ts super quick to do.

Files were then uploaded to the web for viewing, and YUCK!! .. they all looked colour crap!.

Reason is, that they were rendered in the NEF file as aRGB, extracted as they were, uploaded to the net .. where upon uploading all exif data was stripped! .. including colour space.

The browser assumed sRGB, but the file was aRGB .. and they looked like garbage.

So my workflow now, involves the lowest common denominator + least most likely possibility for any monumental stuff ups.

As already said: it makes no difference in real terms if you shoot sRGB or aRGB in real terms when shooting raw.

Because of that and the remote chance that you may need a quick workflow one day in the future .. stick to the lowest common denominator!

You can always select aRGB, or any other colourspace later on for any potentially higher quality uses .. but if you predominantly shoot with the intention to upload to the web .. sRGB!!!

Note that if I had used CNX2 to create those jpg files in a batch process the issue of mismatched colourspace would have never happened in the first place.

CNX2 changes the colourspace on the preview jpg file as you do so on the nef file.

Also note that the differences you see in histograms between an aRGB and sRGB NEF(as per your examples) almost perfectly reflect something I see a lot too. Not all images do this, and the differences is scene dependent.

NOTE: if you use other software to edit your nefs, you probably won't see any of this(I never have), as they don't write their edits to the nef file.(note that CNX-D also doesn't do this to the nef file).

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