At first sight Slave Ship seems to depict a beautiful sunset over a tumultuous sea. A Turner tactic to lull you in. A stark counterpoint to the horrors and barbarity that are the real subject. For this is a political picture, campaigning powerfully and successfully for the abolition of slavery.

British participation in the slave trade was illegal from 1807 and slavery in the British Empire from 1833. Turner exhibited this picture at the Royal Academy in 1840 to coincide with the World Anti Slavery Convention held in London. This led to the British to ban, from 1850, slavery by all nations. Wielding the power of Pax Britannica and of the Royal Navy as global policeman. The painting was initially owned by the art critic John Ruskin, but eventually the emotional burden of ownership became too much for him so he sold it. In America it was then exhibited in 1877 at the Museum of Fine Arts, Boston where it was to pay an important part in their abolitionist debate, American slavery having been finally abolished with the 13^th amendment of 1865.

Ruskin’s introduction to the painting is evocative: “But, I think, the noblest sea that Turner has ever painted, and, if so, the noblest certainly ever painted by man, is that of the Slave Ship, the chief Academy picture of the Exhibition of 1840. It is a sunset on the Atlantic after prolonged storm; but the storm is partially lulled,and the torn and streaming rain-clouds are moving in scarlet lines to lose themselves in the hollow of the night.”

The picture’s subject matter is in its full original title “Slavers Throwing Overboard the Dead and the Dying – Typhoon Coming On”. It comes from the common, brutal and macabre practice in the Middle Passage route of the Atlantic slave trade of throwing unwell slaves overboard because they were insured against drowning, but not against death by disease. And specifically it refers to the voyage of the Zong in 1783, when 132 slaves were killed in this way. Just perishable goods damaged in transit and discarded.

Turner’s great friend and patron from the late 1700s till his death in 1825 was the landowner, MP, writer and political activist Walter Ramsden Fawkes who had campaigned alongside William Wilberforce for the abolition of slavery. Turner had strong convictions about this great political cause of the era. His political convictions also meant that he took an anti war stance with his oil painting The Field of Waterloo of 1818, which annoyed so many people that it was kept locked up for decades. He also campaigned for voting reform with his watercolour Northampton of 1830, which is evocative of the French Revolution.

Turner was Professor of Perspective at the Royal Academy for 30 years, so unsurprisingly in Slave Ship he has used many tactics to create a believable fictive space and to suspend our disbelief, so that the full terror hits home. The composition is painted from an elevated perspective, as if looking down from the deck of another ship. The reflected glare from the sun cuts a trough through the tumult, providing our main reference and forming a Christian cross with the horizon. Other lines within the painting point towards the sun as vanishing point, comparative scale between the foreground objects and the ship reinforce the effect.

Ruskin certainly uses purple prose when evoking the composition: “The whole surface of sea included in the picture is divided into two ridges of enormous swell, not high, nor local, but a low, broad heaving of the whole ocean, like the lifting of its bosom by deep-drawn breath after the torture of the storm.”

The painting is totally asymmetrical and largely devoid of detail. The ship in the left distance is a spectre sailing towards a dark vastness (or is it a rocky coast with breakers at its base?). This imagery can be seen as nature’s condemnation of the act, of divine retribution. In the foreground are the dead and dying slaves, being feasted upon by sea life and abandoned to their fate, placed close to the picture’s viewer for maximum horrific impact.

The use of tone is dramatic and compelling. The darkened semi silhouette of the ship straddling the lightest and darkest areas of the picture. The overall lightness of the right of the picture contrasting with the overall darkness of the left hand side. And through it all the searing brightness of the sunset bisecting the whole composition and making it into a sort of tryptych. The sky to the left, above the ship, is torn and violent whilst to the right it is calm and tranquil, with patches of blue.

Whilst the light should be coming towards us from the sunset, Turner has used artistic license to have it coming from many directions, for instance illuminating our side of the ship and of the manacled leg sticking out of the water. This freedom allows him to model the sea so that the waves are tangible, with real form and volume, whilst at the same time being engaged in violent turmoil and movement. Form is also used for the leg, which is the most sharply defined and detailed element in the whole picture. Also for the fish and for the sea monsters.

With his visits to Venice in 1819 and 1833 Turner increasingly used light and colour instead of detail in his painting and from the 1830s his style became looser so as to often be at the point of abstraction. We see this in about 30 of his works from the 1840s that critics of the day regarded as “unfinished”.

Turner took advantage of a whole range of new synthetic pigments which allowed him to create colour effects never seen in art before. Chrome orange and chrome yellow, cobalt blue, viridian and cadmium yellow. He laid down the major shapes of a composition with primary colours then built the picture we see on top using impasto, applied with pallet knives and his hands and fingernails, as well as with brushes. With the colours largely mixed on the canvas.

Slave Ship is principally a painting of colour, used expressively to engage with and stir up our emotions. The thinking behind this can partly be attributed to the 18^th century Enlightenment philosopher (and politician) Edmund Burke and his concept of the “sublime”. Part of which states that we experience enhanced emotion in the face of nature and that the terror of something violent and horrible became pleasure when revealed as a fiction. As when we experience suspended disbelief at the realism of Turner’s painting which is then replaced with the realisation that we are looking at a picture.

The intense pale yellow light of the sun seems to almost set the sea on fire. A wide range of yellows, oranges and reds dominate the sky and, in darker tones, the sea. To the left of the picture these become purples and the darkest of blues with a great sheet of white spray providing a contrast. The hands of the drowning slaves, rising up from the water, some distinct and some less so, are each just a few strokes of pure colour. Patches of sea around them stained in blood red. The scavenging seabirds are likewise just flecks of white, some partially outlined in black, standing out against the colours.

Ruskin definitely understood that this picture was all about colour: “Between these two ridges, the fire of the sunset falls along the trough of the sea, dyeing it with an awful but glorious light, the intense and lurid splendour which burns like gold and bathes like blood.”

As a Romantic painter (as were Delacroix and Gericault) Turner was less concerned with the accuracy of a painting than with its emotional impact. So in Slave Ship there are several anomalies that make it more a work of fiction than of fact. The fish swimming on top of the water, the two sea monsters bearing down from the right and the iron shackles that are managing to float. But Turner obviously believed that the effect of these on our feelings would leave us immersed in the image and not lead us too quickly into rationality.

Fundamentally this is a very simple picture, a stormy seascape with sunset and distant ship with a few human remains in the foreground. All painted with indistinctness and little detail. What sets it apart is the horror of the depicted events and the Romantic painting style of Turner which maximise the emotional impact on the viewer. As an overall artistic concept it is complex and subtle, it walks many potential fine lines. For instance over sentimentality, clarity ofmessage, relevance to audience, understatement, over politicising, disbelief and excess beautification. That Turner carried all this off makes it a great work of art.

Ruskin quotes from Modern Painters 1843