The only white paint colors that look "dirty" in a north facing room are white paint colors with the wrong chroma - that are actually, literally "dirty".
What most people mean when they say a white is "dirty" is that it's a dull, muted color. Whether you use the word dirty, dull or muted, they all speak to the same dimension of color which is chroma.
The meme "white paint colors won't come to life in a north facing room" started with Donald Kaufman.
After reading his books it is clear that he doesn't understand chroma. (Or any of the psychological dimensions of color for that matter.) I'd say Kaufman is the most overrated "color expert" there is but there are plenty more who'd beat him out for the title.
For every one person who says you can't use white in a north facing room, you'll find another who will tell you they have and they love it.
So who's right? How can BOTH possibly be true?
The difference between the ones who love it and the ones who don't, is the ones who love it stumbled on the right white and it worked.
To find the right white for your space, you have to have a plan.
Step one is ignore the blogs, ignore all the stupid crap on Pinterest.
Start with this list.
Get chips of the colors with a Chroma value less than 0.40.
If it's more than 0.40, don't bother.
I don't care if it's "warm" or "cool" blah, blah, blah.
Doesn't matter.
In a north facing room you either have to have a little chroma or a lot of chroma.
Has absolutely nothing to do with LRV.
It goes south when the pitch of chroma is wishy-washy not too clean yet not too colorful.
You gotta have one or the other.
A clean white or a colorful color for a north facing room.
Just because you have a plan to partner the right pitch of Chroma with the inherent light you have to work with doesn't mean you're guaranteed to like it, btw.
But it gives you better odds than randomly, haphazardly trying a bunch of colors.
I'd start with BenM's White, SW's Extra White and PPG's Delicate White. (line 'em up in that order)
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