Author Topic: Color space date showing up from unknown source  (Read 3137 times)

Tarn

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Color space date showing up from unknown source
« on: March 13, 2013, 03:10:38 AM »
Hi Phil

I discovered this while trying to delete the color space information that my Olympus E-500 was storing in the files. As you can see in the first run, both files report sRGB as the RawDevColorSpace as sRGB, and the ColorSpace is sRGB for P3138172.JPG (first file), and Uncalibrated for _3138171.JPG (second file). P3138172.JPG is, in fact, shot in sRGB color space. _3138171.JPG however, is shot in Adobe RGB. My intent was to remove the color space info from the tags and let PhotoShop figure out what color space they were in. However, as you can see, I could not delete the tags, nor remove the data from them.

Interesting result though... after trying to removed the ColorSpace tag, it now has "Adobe RGB" in it. How did that happen, and where did the "Adobe RGB" data come from?

Sample files are at:
www.dustylenzkapp.com/Dump/_3138171.JPG (212Kb)
www.dustylenzkapp.com/Dump/P3138172.JPG (235Kb)

Code: [Select]
U:\Working>checkcolor .

U:\Working>et --ext .db -Filename -"*color*" . -s
======== ./P3138172.JPG
FileName                        : P3138172.JPG
ColorControl                    : 96 4096 2944 4096 16 128
RawDevMemoryColorEmphasis       : 0
RawDevColorSpace                : sRGB
ColorMatrix                     : 498 -164 -78 -52 360 -52 -2 -164 422
ColorSpace                      : sRGB
ColorComponents                 : 3
======== ./_3138171.JPG
FileName                        : _3138171.JPG
ColorControl                    : 96 4096 2944 4096 16 0
RawDevMemoryColorEmphasis       : 0
RawDevColorSpace                : sRGB
ColorMatrix                     : 332 -12 -64 -50 360 -54 -2 -136 394
ColorSpace                      : Uncalibrated
ColorComponents                 : 3
    1 directories scanned
    2 image files read

U:\Working>et -P -overwrite_original -colorspace= .
    1 directories scanned
    2 image files updated

U:\Working>checkcolor .

U:\Working>et --ext .db -Filename -"*color*" . -s
======== ./P3138172.JPG
FileName                        : P3138172.JPG
ColorControl                    : 96 4096 2944 4096 16 128
ColorSpace                      : sRGB
RawDevMemoryColorEmphasis       : 0
RawDevColorSpace                : sRGB
ColorMatrix                     : 498 -164 -78 -52 360 -52 -2 -164 422
ColorComponents                 : 3
======== ./_3138171.JPG
FileName                        : _3138171.JPG
ColorControl                    : 96 4096 2944 4096 16 0
ColorSpace                      : Adobe RGB
RawDevMemoryColorEmphasis       : 0
RawDevColorSpace                : sRGB
ColorMatrix                     : 332 -12 -64 -50 360 -54 -2 -136 394
ColorComponents                 : 3
    1 directories scanned
    2 image files read

U:\Working>

If you are wondering what I am trying to do, I have some files that I renamed using the 990615-1955.ext format and did not preserved the original _6151955.ext, or P6151955.ext file name. 99% of my files are in Adobe color space. But I am trying to identify the few that are actually in the sRGB color space so I can reconstruct the original filen ames with the proper "_" or "P".

Thank you for your time.

Phil Harvey

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Re: Color space date showing up from unknown source
« Reply #1 on: March 13, 2013, 07:13:16 AM »
Maybe this will answer some questions.  Using the suggestion of FAQ 3:

Code: [Select]
> exiftool ~/Desktop/*313* -colorspace -G1 -a
======== /Users/phil/Desktop/P3138172.JPG
[Olympus]       Color Space                     : sRGB
[ExifIFD]       Color Space                     : sRGB
======== /Users/phil/Desktop/_3138171.JPG
[Olympus]       Color Space                     : Adobe RGB
[ExifIFD]       Color Space                     : Uncalibrated

And from the EXIF tags documenatation:

    ColorSpace
    (the value of 0x2 is not standard EXIF. Instead, an Adobe RGB image is indicated by "Uncalibrated" with an
    InteropIndex of "R03". The values 0xfffd and 0xfffe are also non-standard, and are used by some Sony cameras)
    0x1 = sRGB
    0x2 = Adobe RGB
    0xfffd = Wide Gamut RGB
    0xfffe = ICC Profile
    0xffff = Uncalibrated


- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

Tarn

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Re: Color space date showing up from unknown source
« Reply #2 on: March 13, 2013, 02:59:33 PM »
Hi Phil.

    ... (the value of 0x2 is not standard EXIF. Instead, an Adobe RGB image is indicated by "Uncalibrated" with an
    InteropIndex of "R03".
The values 0xfffd and 0xfffe are also non-standard, and are used by some Sony cameras)
    0x1 = sRGB
    0x2 = Adobe RGB
    0xfffd = Wide Gamut RGB
    0xfffe = ICC Profile
    0xffff = Uncalibrated

When you say an Adobe RGB color space in indicated by "Uncalibrated" with Interopindex of "R03", is that just for this camera (E-500); for any, or most Olympus images; or most any manufacture (Canon, Sony, Nikon, etc)? Would these two example be something that I could search for as a definitive indicator of an Adobe RGB color space? Or if not definitive, would it be a "I'm pretty sure it is" type of indicator?

Could I search for "0xffff" instead of "-Tag"? For example, could I issue the command:
-Filename -0xfff .
with the search returning the file name (and 0xfff value) for any file that has the "0xfff" tag? Or do I need to know the tag nomenclature, or name?

With that, is there a way to search a file for the specific text "Uncalibrated" in any tag, no matter what tag it is? Or do I need to know a tag name in order to search it?

That page on Exif tags is begining to make sense to me now. Thanks.

Phil Harvey

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Re: Color space date showing up from unknown source
« Reply #3 on: March 13, 2013, 04:50:03 PM »
The Uncalibrated+R03 method of designating an Adobe RGB image is, I believe, part of the DCF specification, so it applies to all JPEG images.

To process only images wtih an Uncalibrated ColorSpace, use -if "$colorspace eq 'Uncalibrated'"

- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

Tarn

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Re: Color space date showing up from unknown source
« Reply #4 on: March 13, 2013, 08:46:48 PM »
Phil

That is exactly what I was looking for! Thanks.

You say that it is part of the DCF specification and applies to all JPG images; would this apply to the corresponding ORF and NEF files as well?
I set my cameras to save a RAW file, and a JPG file for each shot. So I could use the same search to identify the RAW files at the same time, yes / no?


Phil Harvey

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Re: Color space date showing up from unknown source
« Reply #5 on: March 14, 2013, 07:13:29 AM »
First, RAW image data has no color space.  It is raw sensor data.  The camera may record the color space settings in a RAW file, but only for applying during development of the image.

Second, proprietary RAW files are proprietary format, and therefore not subject to the DCF specification.

The the answer is "no" on two counts.

- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

Tarn

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Re: Color space date showing up from unknown source
« Reply #6 on: March 15, 2013, 02:17:38 AM »
I (almost) knew that.

As soon as I read "... RAW image data has no color space.  It is raw sensor data ..." I realized the obvious. RAW is just that, RAW. Nothing added or subtracted.

Sorry for the dumb question. And thanks for the answer.