There's a scene near the end of Mike Leigh's award-winning 1996 film, Secrets and Lies, in which actor Timothy Spall, playing emotionally put-upon husband and brother, Maurice, cries: "Secrets and lies!

We're all in pain! Why can't we share our pain!"

It's a key moment in the film which must surely have resonated with each and every viewer. Every family has it's secrets. Some remain hidden and some are forced out into the open by hook or by crook. Secrets have a habit of being outed.

For Bearsden-based artist, Melanie Sims, a discovery in her late teens about her family history led to her digging into the past and unearthing the story of her late mother' Sybil's older sister, Doreen.

"I remember finding a black and white photograph of a little girl and asking my mother about her," says Sims. "From her reaction I could see I had stumbled on something. She didn't want to lie but told me the bare minimum. That it was her older sister and that she had been in a home. As a teenager you are self-obsessed, so I didn't really pursue it then. It was only years later, after my mother died, that I decided to try to find out about Doreen."

Sims has now unpicked this story about her "lost aunt" and turned it into an exhibition, which opens tomorrow at The Lillie Gallery in Milngavie.

The show combines photographic works, installations, textiles and poetry to great effect to tell the story of Doreen, who died in 1967 at the age of 41, in The Whalley Asylum, Clitheroe.

As Sims and her own sister, Fiona, discovered, their aunt Doreen had been in residential care since she was a child of four or five. She suffered from a severe form of epilepsy. In one set of records which the sisters found, noted when Doreen was 39 in 1965, it seemed these fits occurred on a regular basis. "She appeared to take her time to recover," says Sims. "It makes for grim reading. The terminology in one describes her as a 'spastic crippled idiot'."

It's not the first time that Sims has used her own family as a starting point for examining the ties that bind we human animals together. In 2010, she staged an exhibition called The Memorandum Series at The Park Gallery in Falkirk. In this show, she remembered and recorded a specific emotional journey; her response to the death of her mother, Sybil.

One of the most affecting exhibits in The Lost Sister is a large double-sided freestanding diptych. On one side, there is a grainy black and white image of a smiling chubby-cheeked Doreen and on the other is Sybil, who was 12 years younger, at a similar stage.

Sims and her sister spent over a year chasing down the few remaining records which documented Doreen's life.

"With so little information to go on," explains Sims, "I realised this project wasn't about trying to tell the story of Doreen. That was lost forever. What was really pulling at me were questions of connection, broken bonds, denial and loss. My focus became how to express the intangibility of a lost personal history; to find a visual language for it, and to lament my Mum's loss while articulating the importance of the sister bond in my life."

Almost 50 years after Doreen's death she finally has her place in this poignant and beautiful exhibition.

The Lost Sister opens tomorrow at the Lillie Art Gallery, Station Road, Milngavie and runs until August 13.

Melanie Sims will give a talk at the gallery on Saturday July 25 at 2.30pm

www.mjs-photography.com