Isaac Julien's 2019 film, The Lessons of the Hour, is here shown in its UK and European premiere in ten screen installation, an interpretation of the life of Frederick Douglass, the brilliant and forward-thinking orator, writer and philosopher who began life in slavery in Minnesota before escaping and writing about his appalling experiences in a series of autobiographical works. Shot and located partly around Edinburgh itself, notably on Arthur's Seat, with reference to the important time that Douglass spent in Scotland agitating – in eloquent and brilliant fashion - for the abolition of slavery and the emancipation of women, it is a superbly shot and stunning visually, the half-hour whole a series of evocative vignettes and powerful images, threaded through with Douglass' powerful narrative, not least the hard-hitting and uncompromising 1894 speech after which the film is named.

Colours predominate, giving a vibrancy, an immediacy, from the orange of the autumn birch to the blue of Douglass' cloak as he stands, like Caspar David Friedrich's Wanderer above the Sea of Clouds (although here, a light Edinburgh haar), ever wandering, walking, relentless, as if reflecting his long, resolute journey to freedom, his determination in the fight for the rights of fellow enslaved and other oppressed people, particularly women. Some of the women in his life are here too – his first wife Anna, resolute, and Eliza Wigham of the formidable and brilliant Edinburgh Ladies Emancipation Society.

The audio is as rich as the visuals, although I must admit I occasionally found the words difficult to hear. In the soundtrack, sounds segue, shifting meaning, as Julien's Douglass walks through a forest and we hear the sound of wood creaking, first bringing to mind the ships that brought Africans to the Americas, or the ship that brought Douglass to freedom in Europe, but quickly becoming the creak of rope on a branch after a lynch mob has passed through. As the unnamed feet sway starkly in black and white, centrestage in Julien's film, the moment recalls too – along with footage from Baltimore in 2015 - the fact that the horrific practice of lynchings, which rose exponentially in the wake of the emancipation of enslaved people in the late 19th century has still not been entirely banished from parts of the American society that Douglass worked so hard to improve, even if the rope and the tree are no longer the main instruments.

Frank Walter (1926-2009), the late Antiguan artist whose previously unseen “spools” series “Music of the Spheres” is the subject of the Ingleby Gallery's EAF offering, was himself the descendant of enslaved people, but also of the enslavers, counting along the way a white German sugar plantation owner and one of his black female slaves. Walter, who had become the first black plantation manager in Antigua, naturally struggled with this dichotomy in his heritage and identity, trying to make sense of it through a fantastical reimagining (entirely faithfully on his part) of his own ancestral back-catalogue, styling himself in later years as the 7th Prince of the West Indies, Lord of Follies and the Ding-a-Ding Nook whilst increasingly distancing himself from society, writing and making art from a hillside shack. First shown by Ingleby in 2013, his work was recognised internationally in 2017 when it filled the inaugural Antigua and Barbuda Pavillion at the Venice Biennale. His pieces range from the abstract to the figurative, quasi-visionary, always interesting.

Each work here is rounded like an oculus – inspired, it is said, by a somewhat hallucinatory period spent incarcerated on a ship bound for England - as if reflecting the mind's eye, or just simply the eye, Walter intent on the focusing-in on a subject, a moment, a transitory thing that has veneered itself on to the lens, a representation of the fact of looking. Perhaps it came in part with the great unresolvable weight of his dual heritage, perhaps being easier to focus in on the detail one step at a time - the beauty and shadow of a plate of persimmons, the brilliance and freedom of a yacht in full sail, the flight of birds, the absolute cut-off of the horizon, the possibility of beyond. The works in this installation segue from a view of the window in the shack where he spent the last 15 years of his life – a clue here in the roundness containing the rectangular window view, the looking out to a looking out – to a smoking factory stack on the coast, in an easy ride of visual association.

The sculptures are collected on an asymmetrical plinth in the centre of it all. These small, rough, polished mahogany works, some more abstract than others, whether an assemblage of cones making a bird, or a carved whaleish creature, are the sky and sea of Antigua – and perhaps of an imagined mythology, personal or otherwise – each with a tactility that speaks its own truth.

Christine Borland's EAF show, "In Relation to Linum", at Inverleith House in the Royal Botanic Gardens is a somewhat enigmatic representation of the growing processes and qualities of flax, the plant which produces linen and linseed. Borland's work is always thoughtful, carefully done, and it is so here, but this is underwhelming stuff, with little of the story of flax, its history, or anything which might give weight to the investigation of process which Borland so assiduously completes.

Having originally meant to plant a swathe at the Botanics before Covid put a stop to her plans, Borland quickly sent out seed to volunteer growers around the country (and beyond), who each documented their daily toils in bringing the plant to maturity.

Borland is not, in many ways, helped by her subject, which, when not in brilliant blue flower, is itself a somewhat spindly and underwhelming, if useful, member of the plant family. In one room, ever-expanding tubes contain an example of each of the plant's 100 day journey to full-growth. In another, folded, bent specimens from each of the growers march on spindly legs around the wall. There is a room with flax hanging from ceramic cones as if so many pony tails – the “flaxen mane”, perhaps – opposite its earlier, less lustrous incarnation in the process, matted around more cones. Borland paints on flax paper, then in a rare nod, here, to history - although nothing explicit is made of it - photographs herself in a cloak she has made out of flax to recall the meeting of a Maori elder (who traditionally wore cloaks made from New Zealand flax) and James Cook, and then uses 3d computer representation to reproduce the motions of her daughter sowing, reeping, retting and otherwise cajoling her flax crop. But in the end, there is little flesh on the bone, and we are left with the nagging question – why flax?

Christine Borland: In Relation to Linum, Inverleith House, Royal Botanic Gardens of Edinburgh, Arboretum Place, Edinburgh, 0131 248 2909, Until 3 Oct, Daily 10am - 5pm (last entry to Gardens, 4.15pm)

Isaac Julien: Lessons of the Hour, Scottish National Gallery of Modern Art, Modern One, 75 Belford Road, Edinburgh 0131 624 6200, Until 10 Oct, Daily 10am - 5pm, Advance booking required

Frank Walter: Music of the Spheres, Ingleby Gallery, 33 Barony Street, Edinburgh, 0131 556 4441, Until 25 Sep, Weds - Sat, 11am - 5pm

Don't Miss

If birdsong has become less evident now than it was a few months ago in the heady days – if you're a bird – of spring, then it is still a joy to see and hear the different species and calls that frequent our woodlands, coasts and hillsides in summer, whether the screaming of a group of swifts or the song of the skylark. Down on the Forth and Clyde Canal, the diversity of birdlife is being celebrated this month with a series of abstract sculptures by artists Yulia Kovanova and Lars Koens, who have created sculptures based on the colours and shapes of the constituent parts of 20 species which frequent the canal. A lovely excuse for a walk - if you need one.

Chroma Calls,Forth & Clyde Canal Walkway from The Kelpies to Falkirk Wheel. For further information Until 29 Aug