Colours to display same as printing

If you have an iMac and no calibration device, then from your screen shot it looks like it’s already set properly to the default iMac display profile.

You should never change it to any of the other current choices on that menu, because a display profile should always represent the exact state of that display. A 2024 iMac has a display that should be P3, so in theory the one other choice in that menu that could work is Display P3. But Display P3 would only be correct if the display was measured and found to represent exactly P3. But hitting the target gamut precisely is rare in all but the most expensive displays, so that is why Apple had provided the iMac factory profile by default…it could be a better representation of the true behavior of that panel. But an even better profile would be one generated by a display calibration device.

But anyway, if iMac is currently selected, that should be close enough to correct that it is probably not the cause of colors looking a lot different than before. It’s a lot more likely that the problem is how the colors are being proofed on screen for printing.

Did the problem start when old Macs were replaced by newer Macs? Because older Mac displays only covered sRGB, and the newer Macs with P3 displays can display more saturated colors. For example, if someone specifies a color with RGB values above 200 (high saturation), on an sRGB display that color might display sort of close to the limited CMYK gamut. (It was inaccurate, but it was closer to CMYK so it sort of worked anyway.) But with the P3 gamut, that RGB range might display more saturated.

Here is a huge, huge question: Have you ever used soft-proofing? That means intentionally simulating the document through the printer profile, done in InDesign using the command View > Proof Colors using settings in the View > Proof Setup submenu.

If the answer is no, then you’ve been lucky in the past, and you should learn how to soft-proof. Because on today’s displays with wider color gamuts, soft-proofing is valuable for seeing color as the printer would, not as the screen would, by constraining colors to the printing conditions (ink + substrate + press/printer settings).

If the answer is yes, you have been soft-proofing, then the next question is: What are your settings in the View > Proof Setup submenu? There is a critical follow-up question: In your screen shot, your Color Settings use a CMYK Working Space of Coated FOGRA39. Can you confirm that those are the exact printing conditions you are using with your printing service? Because if that is set incorrectly, the View > Proof Colors command will misrepresent the CMYK colors.

If the display profile is good, and soft-proofing is set up correctly, and soft-proofing is enabled, then the colors on screen will be as close to print colors are you can get on an RGB display.

If any of those is not set correctly, display colors are not really under control, especially on a wide color gamut display which all current Mac displays are.