I’m really wondering why Prophoto was not chosen instead ? Of course, we do know that most output devices are unable to display all the colors of the Prophoto workspace. That’s not the problem. However, computations made in a wider color space and using 16-bit bit depth will be more accurate. Even if the data are eventually converted to a smaller color space at the end of the process (export, printing), it’s better to make the intermediary computations as accurate as possible. In any engineering computation, rounding should occur only at the end. It seems that DxO has chosen to make roundings at the very beginning of the process. This is surprising and unusual when comparing with other similar software.
I guess that using Prophoto or something like the Melissa RGB color space of Lightroom wouldn’t have caused any particular difficulty when developing DOP/DPL. DPL could have been a good opportunity to switch to a more “classical” choice. In the DOP era, I can’t remember having read clear statements about this with an exception in 2012 when a staff member wrote this very funny post :
En novembre 2012, Andy du support technique DxO écrivait ceci :
DxO Optics Pro uses Adobe RGB as its internal working color space. As I pointed out in my previous email, you need 32-bit TIFFs for Prophoto color space. Adobe RGB is about right for 16-bit TIFFs and 16-bit TIFFs are far too small for Prophoto RGB. 32-bit TIFFs do not exist yet.
What you have read on the various forums is incorrect. DxO will give you output files converted to ProPhoto color space if you wish it. However, you need to do a little more reading because a 16-bit TIFF file is not enough to hold all this information, much of it cannot be displayed on anything because it exceeds the capabity of human vision, and requires a 32-bit TIFF to hold it all.
We do not have 32-bit TIFF files yet, the best most expensive monitors cannot yet display the full Adobe RGB gamut, and some of the “colors” in the full Adobe RGB gamut are invisible to humans. You can do this, but you will lose information rather than have something more accurate. See the attached.
Obviously, he still had a lot to learn about color management.