Are there subtle differences between different brands of flat white exterior latex house paint that are noticeable on the painted surface close up?
I don’t know for sure but I suspect there are differences. When I was a kid, we painted my family house both inside and out and when buying paint, we were advised by the salespeople at Sears to make sure to buy enough of the same production lot when buying multiple gallons of the same brand and color paint, because there were subtle differences between lots that would be apparent once the paint dried. So if the same brand and color paint varies from lot to lot, I expect different brands of flat white paint to vary even more. (Plus there are many shades of “white” paint.)
Yes. Paint composition is incredibly complex- different wetting agents, dispersants, rheology agents, colorants. There could potentially be no overlapping ingredients in the paint brands (other than water).
Painted walls will change colour with age, so even touch ups with paint from the same can might not match.
If there is any tinting at all there will be variations between different cans or pails of the same paint. When we repair a wall we paint the whole wall.
Different brands have their own base formulations, and there is no such thing as a pure white in paint.
While the White House does look white, it is actually an off-white.
I heard that Trump wanted to paint it gold when he took up residence, but was persuaded to save that until the second term.