Right. Dominiques show up as a dirtier white rather than a gold. At least that's what I've read in the past.
I think what you're describing is the difference between barred and cuckoo, maybe? Barring is much more crisp and defined. Cuckoo is more 'smudgy' with less clear definition in the transition between the colors.
Also, when out in the sunlight, over time any white on birds can become 'brassy' and look yellowed.
Here's a picture of a very nice dominique cock I took at a show. He won best of breed.