An exhibition in the National Gallery in London is tracing the history of colour in Western paintings from the Middle Ages to the end of the 19th century.<br /> <br />It shows the materials artists used to make colours, and the technical challenges they overcame to master them and create iconic pieces of art.<br /> <br />Al Jazeera's Barnaby Phillips reports from London.<br /><br />Subscribe to our channel http://bit.ly/AJSubscribe<br />Follow us on Twitter https://twitter.com/AJEnglish<br />Find us on Facebook https://www.facebook.com/aljazeera<br />Check our website http://www.aljazeera.com/
