The men and women of Gerringong's Boronia Hostel would lapse into a trance-like condition - or sleep - while portrait artist Xi Hsu was attempting to paint them.
Other times they would wander off, or turn unexpectedly against him.
"[A resident] once sat there for three minutes, then suddenly she looked at me angrily and said, 'What are you doing?'," said Hsu, a doctor of creative arts candidate at the University of Wollongong.
"I'm basically anonymous for them ... after three years."
On Thursday Hsu unveiled his final exhibition at UOW, including a series of portraits of the anonymous dementia patients - many of them unfinished, telling the stories of their subjects' malady.
The works are the result of the artist's incredible years-long study of the condition, during which he would visit the Gerringong dementia facility on a weekly basis.
A well-known portrait artist in his native Taiwan, Hsu told an audience at the exhibition opening he had found parallels between the residents' state and his own feelings of anonymity, as a newcomer to Australia.
The exhibition, Searching for the Vanishing Subject in Portraits of Dementia, is in UOW's Creative Arts Building until May 23.