Decorators white is going to look like a very, very, very light grey compared to a ceiling white or any kind of ultrawhite trim. Like VERY light grey. In my last home I had large areas of walls painted decorators white. In low light situations (especially at night) you could see the grey shade more easily. I mean, it didn’t look like grey paint per say. It still looked very white, but held right next to it, you can usually see the grey. I really liked it! (It looks terrible next to a soft white, creamy white, or yellowish white though... I had to re-paint a lot of trim when I chose decorators white, LOL!)