different behaviour when opeing a TIFF vs a JPEG

[stuck]

There has (again) been discussion on the DxO forum about whether or not PhotoLab actually embeds an sRGB ICC profile when exporting a file with option for the ICC profile explicitly set to be sRGB.  My experience is that it doesn't embed, it just sets metatdata tag(s) that say the colour space of the file is sRGB.  In the course of trying to demonstrate that I've found that Photo2 handles a TIFF 'sRGB' export from PhotoLab differently to the way it handles a JPEG 'sRGB' export from PhotoLab:

• If I export a RAW file to a TIFF, explicitly setting the ICC profile to sRGB then in Affinity Photo with it’s working colour space set to Adobe RGB then I get the warning about the document being unprofiled.

• If I export a RAW file to a JPEG, explicitly setting the ICC profile to sRGB then in Affinity Photo with it’s working colour space set to Adobe RGB then I get a different warning that makes no mention of the file being unprofiled.

Does this behaviour mean that:

• When Affinity Photo opens a TIFF file that has metadata saying it’s in sRGB, Affinity Photo is not seeing that metadata. Thus, as there is no profile embedded, it thinks it is unprofiled.
• Whereas when Affinity Photo opens a JPEG file it does see the ‘sRGB’ metadata and thus gives the different warning.

If so, is this a bug in the way Photo2 is opening TIFFs vs JPEGs?

[Ldina]

@stuck I don't use PhotoLab, so I don't know how those files are saved, whether profiles are embedded, etc.

Can you upload a sample JPG and TIFF exported from PhotoLab that are exhibiting this behavior? I'd be curious to know myself.

[stuck]

1) Set Photo 2's 'RGB colour profile' to something other than sRGB, and restart Photo 2 to ensure that setting is in effect.

2) Open these images one at a time and watch out for the warning in the top right once the file has loaded.  NB the warning doesn't persist for long.

a) DxO_sRGB.tif
DxO_sRGB.tif

b) DxO_sRGB.jpg

 

No comments please on the actual image itself, I know it's rubbish, it's just something to illustrate the warnings I'm seeing.

 

 

[Ldina]

@stuck, Thanks for the uploads.

Interesting. When viewing these using Finder on my Mac, both the JPG and TIFF show sRGB color space. 

When viewed in XnViewMP, the JPG doesn't show any profile. The TIFF shows the file as sRGB.

I opened both in AfPhoto v2.6.0. The JPG opened as sRGB without any warning, even though XnViewMP shows no profile at all (but Finder does list sRGB). The TIFF file opens with a warning that it is an unprofiled document (even though Finder and XnViewMP say it is an sRGB document) and assigns my Affinity working profile, which I have set to DCI-P3.

Opening the Affinity Metadata panel, the JPG lists sRGB as the color space, but the TIFF shows uncalibrated. Something seems wonky here. Perhaps it is, as you say, where this tag is written in metadata, or how the profile is saved (or not) in the document.

As a control experiment, I opened one of my old TIFF files created in PS and saved with Adobe RGB profile. It opened properly in Affinity and honored the Adobe RGB profile.

EDIT: In AfPhoto, I Assigned sRGB to the TIFF file (after it opened and assigned my default DCI-P3 profile). After assigning sRGB manually, the Metadata Panel shows sRGB color space. Prior to manually assigning sRGB to the file, the Metadata Panel shows "uncalibrated" as the color space. Perhaps it is the way DxO is writing the profile to the file or into metadata. It could be Affinity Photo itself. I don't have a full installation of EXIF Tool, just what is included in XnViewMP. 

[David in Яuislip]

Яesults from Яuislip
Built-in profiles using dropdown in Photolab export

exiftool -icc_profile -b -w icc P1140982BIProphoto.jpg    1 output files created
exiftool -icc_profile -b -w icc P1140982BIARGB.jpg    1 output files created
exiftool -icc_profile -b -w icc P1140982BIARGB.tif    1 output files created
exiftool -icc_profile -b -w icc P1140982BIP3.jpg    1 output files created
exiftool -icc_profile -b -w icc P1140982BIsRGB.jpg    0 output files created
exiftool -icc_profile -b -w icc P1140982BIsRGB.tif    0 output files created

Imported from C:\Windows\System32\spool\drivers\color
exiftool -icc_profile -b -w icc P1140982ImportsRGBicc.jpg    1 output files created
exiftool -icc_profile -b -w icc P1140982ImportsRGBicc.tif    1 output files created
exiftool -icc_profile -b -w icc P1140982ImportsRGBicm.jpg    0 output files created
exiftool -icc_profile -b -w icc P1140982ImportsRGBicm.tif    0 output files created
exiftool -icc_profile -b -w icc P1140982ImportARGB.jpg    1 output files created

Or in plain English, the built-in sRGB profiles don't embed, neither does imported "sRGB Color Space Profile.icm"

Photo V1 opens them all correctly. If set to convert and warn then it does otherwise it doesn't and shows the correct profile
So if I want an embedded sRGB profile from Photolab I use an icc profile in C:\Windows\System32\spool\drivers\color
Sorry for the nerdyness

[stuck]

1 hour ago, David in Яuislip said:

...Or in plain English, the built-in sRGB profiles don't embed...

Which what I thought, thanks for the nerdyness that  confirms my belief.

The question still remains though, does it not, why does Photo 2 read a PhotoLab TIFF in sRGB differently to a PhotoLab JPEG is in sRGB?  Is it:

a) that PhotoLab writes the metadata in different ways depending on file type (that would not surprise me one bit)

or

b) that PL writes the metadata in the same way in both files types but Photo 2 is reading that metadata in different ways?

[David in Яuislip]

Here are exiftool dumps for tif & jpg if you wish to compare, I hope you'll forgive me if I bale now as there is a pub that needs my custom

TL:DR Both contain
Color Space : sRGB

ExifStuff.zip