Custom Monitor profile and SRGB conversion: why it is so different?

[lucchett]

Hi,
I work on a IPS panel wide gamut with Custom monitor profile.
the color space is about that of Adobe RGB.

I do my processing with the custom profile active

in Pixinsight, when I switch (assign) to sRGB before the web publication the difference in saturation and contrast is dramatic (very low saturation and low contrast in the sRGB).

In day light photography (which I do in a different application) of course there is a small difference but changing the profile is not that hard and color are always well remapped.

The difference is evident right from the beginning, after color calibration.
More, I can usually restore saturation and contrast after the change of color profile.(which tells me that the color are not out of gamut and change of the profile shouldn't be an issue).


so...:

1) am I missing something/ need to configure something?
2) shall I move to sRGB at the very beginning? (easy, it doesn't seems the right answer)

Correcting for saturation at the end it is no sense as it means repeating a process and in a very simple way.


Thanks a lot,
Andrea

[RickS]

Hi Andrea,

I think it makes sense to process in a device independent colour space so I use AdobeRGB for all my colour data.  Device independent spaces have nice properties that your monitor profile may not, e.g. any colour with equal R, G and B values will be grey.

How do you "assign" to sRGB?  If you just tag the image as sRGB without doing any conversion then I would expect you to lose saturation as you're interpreting data from a wider gamut in a narrower one.  You need to do a colour space conversion.  I use ICCProfileTransformation if I want to convert an image to sRGB and that always works well for me.

Cheers,
Rick.

[lucchett]

Hi Rick,
 I use "assign ICC color profile", in the same menu.
I didn't notice the ICC Profile transformation.

Do you know what's the difference?

working in a canned profile should always give you a final "change" after profile transformation, compared to the ideal profile.
In my case, adobe rgb is very, very close, it make sense to use it.

I start thinking something is not properly configured in my color management settings.
thank you Andrea

[RickS]

Hi Rick,
 I use "assign ICC color profile", in the same menu.
I didn't notice the ICC Profile transformation.

Do you know what's the difference?

Andrea,

Assigning a profile will just attach the new profile and leave the data the same.  The data will then be interpreted in the new space and will look different.

Using ICCProfileTransformation to convert to a different profile will modify the data to preserve the appearance of the image in the new profile as far as possible (where colours are out of gamut the rendering intent will determine what happens.)

You should definitely be converting and not assigning.

Cheers,
Rick.

[lucchett]

Yes, Very good.
Thank you Rick