100 K Black converted to Rich Black when changing Colour Profile in Publisher Bugs found on Windows Posted November 4 I think that this is "by design". Affinity apps do not have a specific [Black] or [Registration Color] color swatches, as does InDesign, so the mere black (K) values will be converted to CMYK according to the specs of the color profile. InDesign actually behaves similarly if you create a separate K100 value (instead of using [Black]). What is more serious is that Affinity Publisher does NOT change the color values of user-defined color swatches, accordingly, resulting in break of all (non-spot) color assignments, including global. I would not use the "Convert" option unless it is absolutely necessary. Normally it shouldn't be. If the change of color profile is needed within the same color mode (.e.g, just using different CMYK profile), I'd use the "Assign" option. That does not change color values, but would still affect the way the RGB images are exported (e.g., this could be useful if you change from coated to uncoated, or vice versa, and just want it to affect the imported RGB values but not your text and internal vector graphics, or just want to assign the printer requested color profile). This kind of change should be done at this stage rather than in export settings (where CMYK values would be converted similarly if the document and target CMYK profiles are in conflict). You mention "Windows version only". I have currently no macOS version of any of the Affinity apps installed so I cannot check this, but I find this quite surprising. Could you rechecki and confirm this?