If done properly, a changeover should be virtually unnoticeable to an audience.
From the en.wikipedia.org
With a good transfer the resolution loss will be negligible, perhaps unnoticeable.
From the post-gazette.com
The more unnoticeable you can make the changes, the less likely you are to suffer.
From the emotionalumbrella.com
So the improvement has slowed to a point where it's almost unnoticeable now.
From the washingtonpost.com
His goal, he says, is to make his showroom-quality repair work unnoticeable.
From the ocregister.com
Then I see a small scar on his head, almost unnoticeable beneath short hair.
From the well.blogs.nytimes.com
He looks backgroundy, and his shockingly mellow demeanor makes him extra-unnoticeable.
From the time.com
Turbo lag was only a minor issue, and for the most part was unnoticeable.
From the ocregister.com
The screen is crisp and reactive and the software interface is pleasantly unnoticeable.
From the newscientist.com
More examples
Unobtrusive: not obtrusive or undesirably noticeable; "a quiet, unobtrusive life of self-denial"
Not noticeable; not drawing attention; "her clothes were simple and unnoticeable"- J.G.Cozzens
Obscure: not drawing attention; "an unnoticeable cigarette burn on the carpet"; "an obscure flaw"
(unnoticeableness) the quality of being not easily noticed
(unnoticeably) imperceptibly: in an imperceptible manner or to an imperceptible degree; "the power of the Secretary of State in London increased gradually but imperceptibly"