Given a monitor capable of most of the P3 gamut, which is the recommended workflow for generating an ICC profile from ColourSpace + SpaceMan for use in Photoshop under Windows?

I noticed SpaceMan's RGB space only has a limited number of RGB Space entries:

Would I thus:

• Profile the display in it's native gamut.
• Generate a 3D LUT from ProPhoto RGB primaries to the profile above.
• Create a ICC from the 3D LUT using ProPhoto RGB Space (from the list I know this one is bigger than P3)
• Set ProPhoto RGB as working space in Photoshop

?

Basically, yes.
The main part of the workflow is no different from any 'calibration workflow'.

The last part is as per the User Guide.
"The Windows OS colour management Device Profile needs to be set to match the Working Space, as will be used within Photoshop."

See: https://www.lightillusion.com/spaceman_manual.html

Steve

Hi there,

For generating an ICC profile using ColourSpace and SpaceMan for a monitor capable of most of the P3 gamut, you can follow this recommended workflow:

Profile the display in its native gamut using ColourSpace.
Generate a 3D LUT from ProPhoto RGB primaries to the profile obtained in step 1.
Create an ICC profile from the 3D LUT using ProPhoto RGB space.
Set ProPhoto RGB as the working space in Photoshop.
This approach allows you to take advantage of the larger ProPhoto RGB color space while ensuring compatibility with your monitor's capabilities. It should provide a good balance between gamut coverage and color accuracy in your workflow.

Best regards.

A part that confused me was that ProPhoto RGB is defined with gamma 1.8 and D50, but I wanted my profile for gamma 2.2 and D65.

One workaround was to set up the resulting monitor profile as the working space in Photoshop instead of the preexisting ProPhoto RGB. Doesn't feel right, but measuring patches displayed in Photoshop gives correct results, and the greyscale gradient is very smooth.

The D50 value in an ICC profile is not the target display white point.
It is the 'media white point/connection space colour temp'...
Confusing, I know, but such are ICC profiles.

The target white point for the actual colour space can be any value you want to use.
Same with the gamma.

This info may help: https://www.color.org/whyd50.xalter

Steve

I've been digging more into the maths behind this and stumbled upon an interesting question: which are the ProPhoto RGB primaries to use for 3D LUT generation?

Initially I've been naively using the ones from Wikipedia: Red 0.734699 0.265301, Green 0.159597 0.840403, Blue 0.036598 0.000105. But I know believe this to be a mistake as these primaries are relative to D50 and my 3D LUT generation uses D65. They would need to be multiplied with the chromatic adaptation matrix.

CIE coordinates for colour are absolute, not relative.

Steve