Export to JPEG with metadata causes color change

[VinR]

Hi all,

I've noticed the same issue mentioned in few other threads but I though creating a new thread. First of all I've noticed that when I export my images as JPEGs after processing it makes it more reddish in color. This won't happen when I export it as PNG. After few experiments I've noticed that this happens only when I export with embedded metadata. for the same export settings if I uncheck embed-metadata option, then it exports with correct colors (at least it looks like what I see in Affinity). I don't understand how adding metadata would change the colors of the image.

Can someone explain whether this is a bug in Affinity or whether I'm doing something wrong.

I have attached two images exported from same cropped Affinity processed image - one with metadata (more reddish in color) and another without metadata (with normal colors that I expect to see)

Both images with 95% quality

I'm not sure you would see the same difference I see so I attached another image with both images opened next to each other

 

Thank you

 

Processed.zip

Edited July 28, 2019 by VinR

[stokerg]

Hi VinR and Welcome to the Forums,

It appears to be the Colour Profile that is the cause of the red.  When i open your 95-meta.jpg from your ZIP file, it's using the Colour Profile opRGB and other file 95-no-meta.jpg is using the sRGB.  If i assign a standard SRGB profile to the 95-meta.jpg then that looks fine (see attached screenshot).  

Do you have the original image you could upload?  

[VinR]

Hi stokerg

Thanks for the reply, I took another cropped version of the same image (since I cannot share the full image) Attached zip file has the .afphoto file and two jpegs exported one with metadata selected and another without it. I also have included another screenshot of the export dialog box in two different scenarios in order to show you that only difference is "Embed metadata" option.

Thank you

affinity.zip

[- S -]

I’m not sure what workflow you used to create the ‘colorcast.afphoto’ file that you uploaded, however I suspect it was perhaps something similar to this:

– When taking the original image, the Canon settings were set to Adobe RGB in the in-camera settings. Therefore, the CR2 raw file (or out-of-camera JPG) has the colour space set to Adobe RGB in the metadata. The original file name was also probably something like ‘_MG_0125.CR2’ (with an underscore at the beginning of the file name to denote Adobe RGB colour space).

– Then processed the CR2 raw file in the Affinity Photo develop persona.

– Then exported the image as an “RGBA/8 - sRGB IEC61966-2.1” JPG file.

I don’t know the solution to your issue—so I would see what Serif come back with— however what I think is possibly happening is something along these lines:

1) When you export the image as a JPG (or TIF) with metadata embedded, Affinity Photo is converting the file to “RGBA/8 - sRGB IEC61966-2.1” on export, and leaves the metadata in the file. As one of the EXIF metadata fields says the ColorSpace is Adobe RGB, I think the Windows Photos app is reading this and thinks the image is using an Adobe RGB colour space (hence the oversaturated colours).

2) When you export the image as a JPG (or TIF) without metadata embedded, Affinity Photo is converting the file to “RGBA/8 - sRGB IEC61966-2.1” on export, but is also removing the metadata. As the EXIF metadata field that says the ColorSpace is Adobe RGB is no longer in the file, the Windows Photos app treats it as an sRGB file and therefore the colours are the same as what you see in Affinity Photo.

3) When you export the image as a PNG with metadata embedded, Affinity Photo is converting the file to “RGBA/8 - sRGB IEC61966-2.1” on export. Then although Affinity Photo leaves the metadata in the file and therefore one of the EXIF metadata fields still says the ColorSpace is Adobe RGB; I think the Windows Photos app perhaps uses another field to determine the colour space with PNG files—one that has a higher priority than EXIF—and therefore as this higher priority field says the document is sRGB, the Photos app treats the image as sRGB.

[VinR]

3 hours ago, - S - said:

I’m not sure what workflow you used to create the ‘colorcast.afphoto’ file that you uploaded, however I suspect it was perhaps something similar to this:

– When taking the original image, the Canon settings were set to Adobe RGB in the in-camera settings. Therefore, the CR2 raw file (or out-of-camera JPG) has the colour space set to Adobe RGB in the metadata. The original file name was also probably something like ‘_MG_0125.CR2’ (with an underscore at the beginning of the file name to denote Adobe RGB colour space).

– Then processed the CR2 raw file in the Affinity Photo develop persona.

– Then exported the image as an “RGBA/8 - sRGB IEC61966-2.1” JPG file.

I don’t know the solution to your issue—so I would see what Serif come back with— however what I think is possibly happening is something along these lines:

1) When you export the image as a JPG (or TIF) with metadata embedded, Affinity Photo is converting the file to “RGBA/8 - sRGB IEC61966-2.1” on export, and leaves the metadata in the file. As one of the EXIF metadata fields says the ColorSpace is Adobe RGB, I think the Windows Photos app is reading this and thinks the image is using an Adobe RGB colour space (hence the oversaturated colours).

2) When you export the image as a JPG (or TIF) without metadata embedded, Affinity Photo is converting the file to “RGBA/8 - sRGB IEC61966-2.1” on export, but is also removing the metadata. As the EXIF metadata field that says the ColorSpace is Adobe RGB is no longer in the file, the Windows Photos app treats it as an sRGB file and therefore the colours are the same as what you see in Affinity Photo.

3) When you export the image as a PNG with metadata embedded, Affinity Photo is converting the file to “RGBA/8 - sRGB IEC61966-2.1” on export. Then although Affinity Photo leaves the metadata in the file and therefore one of the EXIF metadata fields still says the ColorSpace is Adobe RGB; I think the Windows Photos app perhaps uses another field to determine the colour space with PNG files—one that has a higher priority than EXIF—and therefore as this higher priority field says the document is sRGB, the Photos app treats the image as sRGB.

Thank you very much for your detail explanation, 

You're right the original image out of the camera is something like _MG_0125.CR2. I then adjusted few settings in develop persona and then exported it in Photo persona (once with embed metadata again without embed meta data) So based on your explanation, I now exported another JPEG by selecting Adobe RGB as the color profile, and including the metadata. Now if you look at color space exif data of the images, both are same (Adobe RGB) however this new export has the normal colors (not oversaturated), so I'm not sure this is totally based on the Color space value in the exif data

 

affinity2.zip

[- S -]

2 hours ago, VinR said:

Thank you very much for your detail explanation, 

You're right the original image out of the camera is something like _MG_0125.CR2. I then adjusted few settings in develop persona and then exported it in Photo persona (once with embed metadata again without embed meta data) So based on your explanation, I now exported another JPEG by selecting Adobe RGB as the color profile, and including the metadata. Now if you look at color space exif data of the images, both are same (Adobe RGB) however this new export has the normal colors (not oversaturated), so I'm not sure this is totally based on the Color space value in the exif data

That's what I would expect you to see.

Exported as:
Adobe RGB without metadata = OK
Adobe RGB with metadata = OK
sRGB without metadata = OK
sRGB with metadata = Not OK (due to the EXIF metadata incorrectly telling the Photos app that it's an Adobe RGB image, when it's an sRGB image)

I think it's possibly an oversight/bug, but I don't have time to look into it at the moment.

[VinR]

Thanks @- S -

Yeah I can live with this at the moment, but it is better to track as a bug (or something to investigate further) for future releases. 

Once again thank you