Dundas is a mid neutral grey — LRV 31.8, so darker than a pale office grey but nowhere near moody territory — with a faint taupe-violet softness that stops it feeling industrial. Under warm lamplight it relaxes; in cool daylight it reads properly neutral. Treat it as the calm middle of the scheme and give it things to push against.
Start with the frame. Farrow & Ball All White (LRV 92) on woodwork and ceiling is exactly right — a clean, neutral white with just a faint warmth, so the grey stays crisp without the trim going icy. That 60-point light gap is what makes a mid grey look deliberate rather than dingy.
Then add depth. Paint & Paper Library Blue Blood (LRV 16.4) is a deep inky navy with a cool green-grey undertone — a proper partner for Dundas on joinery, a panelled wall or below a dado rail. Grey and navy is a hard combination to get wrong.
A grey this neutral can tip cold and clinical, so give it one genuinely warm note. Mylands Beehive Place No.140 (LRV 58.6) is a golden, honeyed yellow — in a connecting hallway, on the back of shelving or as the next room's colour, it's sunshine against the grey. On the textile side, natural undyed flax linen does the same job more quietly.
Want a punchier accent? Dulux Fuchsia Falls 2 (LRV 29.8) is a bright, cool magenta-pink that sits at a similar depth to Dundas and sings against it in small doses — a single chair, an artwork. It's seasoning, not a second main course.
Practical advice: test Dundas on the wall that gets the least light first. Mid greys drop a band in poor light, so if it still reads as soft grey — not gloom — in your darkest corner, you're sorted everywhere else. Two coats on a big board, checked morning and evening, and you'll know.