Hello
I wanted to convert some images to blue only, like a cyanotype, with the full range of blue shades my P600 can print on Hahnemühle Photo Rag paper.
In Photoshop, colors of the original photo are converted to blue with the tool "shading transfer curve" (I don't know the exact English words). The shading is blue-black at left, saturated blue at 50% and white at right (or bluish white).
It works well, but I have a lot of out of gamut colors. The number of these colors is greatly reduced if I choose a blue inside the gamut of my color profile for my paper, in the color selector and with the "Out of gamut colors" warning on.

Inside Photoshop, the out of gamut colors are different with ICM Microsoft and with ICM Adobe (ACE).
And, out of gamut colors are different in Qimage, too ! A color inside the gamut in Photoshop, falls outside the gamut in Qimage. Qimage is more restrictive.

Why ? Different threshold ? Completely different color management ?