For 50 years, the songs of Joni Mitchell have left an imprint on the lives of countless admirers.

Though, unlike a tattooist's needle, there's no pressure or pricking exerted in the way her art manages to penetrate our skin.

Rather, it's by way of her soft, meandering melodies, which shimmer and ripple like Autumn winds playing with fallen leaves; her light, open voice that coos and bends poetic words - heartfelt, philosophical and wry.

On Blue, Joni Mitchell brings all of the above masterfully into play. The result is an album that has been a trusted and wise companion to many fans, the long-term and devoted, and those still discovering her genius.

The artwork for Joni Mitchell's 1971 album BluePlaySpace to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume.

As the '60s were drawing to a close, Joni Mitchell's star status was at a heady peak. She'd had hits with 'Woodstock' and 'Big Yellow Taxi', her songs were being covered by popular folk and country artists of the day, and her albums Clouds and Ladies of the Canyon were widely acclaimed.

She decided she needed time away from the hectic media and touring circuit, on some travelling adventures around the world.

The result of those travels informs many of the songs on Blue. You can feel the wandering heart on 'All I Want', the vivid landscapes of a holiday fling on 'Carey' and the postcard home on 'California'.

Romantic love and the strained dynamics of messy relationships make up the good bulk of Blue. Although her voice is soft and pretty, and her touch is light, her words are quietly devastating for their detail and directness.

On 'The Last Time I Saw Richard' she scolds then blows off the cynicism of a friend who ends up in the sort of humdrum domestic routine that he criticises other hopeless romantics for.

Even when she is fantasising about domestic bliss such as on 'My Old Man', she manages to work in some inspired wry humour in lines like: "But when he's gone, me and them lonesome blues collide, the bed's too big, the frying pan's too wide..."

On 'A Case of You', she likens her appetite for an all-consuming love to that which a hardened drinker has to copious grog; "I could drink a case of you and I would still be on my feet"

But there's power in her choice, of knowing the consequences of a love that comes with risk, on getting the advice of a woman who cautions her to "Go to him, stay with him if you can, but be prepared to bleed".

Life had prepared Joni Mitchell very early on for struggle, pain and disappointment. By the time she made Blue, she had already lived through a few lifetimes of experience, having survived childhood polio, a marriage and divorce, and the sorrow of giving up her daughter for adoption.

On 'Little Green' she sings tenderly of the child she gave away, imagining the moments of joy in a separate life, confessing that "you're sad and you're sorry but you're not ashamed".

Joni Mitchell always referred to herself as a painter derailed by circumstance. Indeed, she uses colour directly in reference to her daughter on 'Little Green' and blue as reference to a both a lover and a despairing mood on the album's title track.

She also uses her knowledge of colour application in the way she arranges her songs. It's through her painter's eye for detail - and understanding how small, light strokes can breathe life into her work - which has made her such an exceptionally unique songwriter and musician.

Her most compelling statement is made on a song that wasn't released as a single, but has grown to become a classic in her expansive catalogue.

'River' entices your ear with its familiar 'Jingle Bells' interpolation setting a scene of festive season gatherings and ornamentation, yet her poignant voice lets you know that, emotionally, she's miles away.

It's frosty outdoors and amid the songs of 'joy and peace' in the air, she longs for the warmth of a lover who "loved her so naughty and made me weak in the knees", an unabashed weaving of the sacred and the profane.

There's distance, regret, loneliness, frustration and fantasies of better days ahead. And although she paints a vivid scene, Mitchell knows there's no river long enough to outrun all of our problems in life, nor would we have the stamina to actually achieve it.

With Blue, Joni Mitchell demonstrated the great power of vulnerability and emotional release, which at the time, was uncommon in popular music.

It was an instant success in 1971, and was the start of a run of truly remarkable albums. Yet, 50 years on Blue is the album many return to again and again, to hear the potency of an artist speaking their deepest truths and finding beauty, acceptance, strength and gratitude in the wholeness of the experience.

Unlike the shades of colours and moods she depicted in shifting states of motion on Blue, there is no waxing and waning when it comes to Joni Mitchell's ever expanding legacy.