My LR & foyer were painted in sage & soft blue that were wonderful in summer but made the house feel dismal & chilly in winter. Because we spend more time in cold, often gray weather here, I changed the colors to warm autumnals. While those colors are a little stifling in August (remedy = bring in cooling cobalt blue accessories) , they're great the rest of the year. I haven't had winter downers since painting my LR orange. It's so cheery & welcoming. It also helped to put in larger windows. The abundant winter light makes the new room colors glow. We kind of miss our summery house, but to have a home that makes fall, winter, & early spring enjoyable is worth it. My #1 DS is mildly autistic and has hypersensitivities, primarily smell & touch. But evidently color affects him strongly too. When we moved to the northeast, I was worried about his adjustment (disastrous --another story). I gave him the bedroom with cross lighting, and let him pick out a room color, hoping to mitigate any adolescent depressions. He asked for bright yellow walls. I made a nice room for him: happy face yellow walls, a sophisticated oriental rug with navy & deep red, cherry furniture & off-white matelasse bedding. It was colorful and upbeat without being childish. Well, he hardly was ever in that room. "It's too 'sharp', " he said & moved into our bland basement: light brown "pecan" paneling and oatmeal Berber carpet, blah muddy colored furniture, fluorescent light (it's consistent!). And that's the way he likes it. It's soothing to him. I have since repainted his bedroom a soft gray blue, and he's been using the room a bit, now that it's no longer "sharp".

This happened to me too! Painted poster boards and moved them around the room to make sure I loved the color before painting the entire living/dining room. I did everything I was supposed to, and after two coats it was BABY BLUE!!! I was so upset. But then I held up the paint chip white dove (OC-17) to our trim, and our trim was YELLOW!!! I'd bet your trim isn't white, but rather a yellow or darker cream. Here's a pic. Same color, revere pewter, different trim. The trim on the right is white dove. The trim on the left is old, yellowed oil based trim of unknown name.

I don't have a good picture of that space but I do have a good image of a north facing bedroom where I have Ballet White on walls & ceiling. In this one image you can see all the various undertones that pop out with this color depending on how the light hits it. It's a real chameleon! All the wood work here is Shaker Beige. At the top of the picture note the ceiling is angled and there you can see how Ballet White has a pinky grey tone. On the wall above the shoes it reads much brighter - a grey/taupey white. It is absolutely a 'muddy' color, not 'clean.' I have used it successfully with challenging hard surfaces that I can't change right now (like this orange pine floor, where I have a pinky-taupe faux travertine in a laundry room, and in a guest bathroom with a pinky grey granite countertop). If you don't have a reason to use it, I wouldn't just because it is so variable. IMHO White Dove or Simply White are way better colors and far more consistent across seasons and surfaces. I would paint some large samples and move them around the room. Good luck!

Haven't read through the thread but will share this: I do like the black and white vibe you have going but wouldn't add much, if any, more black. Would definitely want to keep the walls really light in a north facing room so you can keep the furnishings you choose --even dark ones -- and yet not end up with a cave vibe. Would not use wall paper. Strategically placing a mirror can reflect outdoor light from the windows. Might invest in a stand for it ( or create one DIY) and try it in different places. .https://www.overstock.com/Home-Garden/Mirrors/2009/subcat.html?featuredproduct=23050300&featuredoption=38528315&kid=9553000357392&ci_src=17588969&ci_sku=28607771-000-000&cnc=US&cid=302184&type=&targetid=pla-295822288689&track=pspla&gclid=EAIaIQobChMIur-8p7mw7QIVw9SzCh10yw8cEAkYBiABEgLeJfD_BwE