DALLAS (AFP) - Former US president George W. Bush says his new painting hobby has changed his life.

Mr Bush, 66, said that he wanted to keep learning even in retirement - to follow the example of his father, ex-president George H.W. Bush.

"You know what the interesting lesson is though, that you can keep learning in life," Mr Bush told ABC News in an interview to mark the opening of his presidential library on Thursday.

"I don't want to rest. I want to follow the example of president 41 and, you know, sprint into the grave."

Mr Bush senior, 88, has had an active retirement, despite recent illnesses and increasing frailty, and even marked his 85th birthday with a parachute jump.

His son said that he took up painting after learning how the hobby had absorbed former British prime minister Winston Churchill.

"I look at colours differently and I see shadow," said Mr Bush, while making clear he knew the limitations of his work.

"The signature is more valuable than the painting."

The former president said he paints daily and has help from a "patient" instructor.

"I love to paint," he said. "Painting has changed my life in an unbelievably positive way."