The phrase "deepen the impression" is correct and can be used in written English.
It means to make a stronger or more profound impact on someone's thoughts or feelings. Example: "The speaker's passionate words only served to deepen the impression he had already made on the audience."
The forthcoming inquiry into his finances is likely to deepen the impression that the Teamsters, long affiliated with the Mob, remain rotten despite half a decade of efforts to reform them.
You could argue that Haas and his screenwriter, Wendell Steavenson, have planned this deliberately, so as to deepen the impression of a country snarled up in loose ends — how can you hope to impose democratic discipline, after all, when a single dumb crime goes unsolved?
"To be frank, after seeing these reports, I've felt that the way in which a few American media have handled this may deepen the impression that people have held of the arrogance and conceitedness of some Western media," said Hua Chunying, a spokeswoman for the ministry, at a regular briefing in Beijing on Monday.
I do think that the over the top attacks on Acorn will "deepen the impression that the GOP is insensitive and hostile to poor people".
And yet the tape and the transcript do deepen the impression of blithe hypocrisy when it comes to the business of electing an obviously erratic man as President.
"What Republicans are doing for themselves right now," Mr. Garin added, "is deepening the impression that they are the party of Big Oil".
The arbitrary arrest of the cardinal, the pressure put on his judges, and his final disgrace deepened the impression of the king's weakness and the autocratic nature of his government.
The fact that Lord Howell is the father-in-law of Britain's Conservative chancellor of the Exchequer, George Osborne, an advocate of fracking, only deepened the impression of a north-south contest cemented in place by political rivalries.
Their effort to disenfranchise poor, black, Hispanic, and student voters in many states deepens the impression that Romney's remarks about the "forty-seven per cent" were a matter not of "inelegant" expression, as he later protested, but of genuine conviction.
Meanwhile the steady drip of positive retests from Beijing 2008 and London 2012 – while ultimately good for the sport – has deepened the impression that more needs to be done to stop doping.
It was one of a number of cases that have deepened the impression that, in the words of the former Black Fern and current MP Louisa Wall, the attitudes of rugby players in the country "have fallen behind society".
