Walton-on-the-Naze, 1860 by Ford Madox Brown (Birmingham Museums Trust) This week museums all over the world have been taking part in #MuseumRainbow on social media. It's been wonderful to see all kinds of unique collections shared globally in this joyful way. Inspired by all the bright colours that have filled my computer screen, it felt like the right time to share one of the stories behind a striking painting featured in the Walker's exhibition, 'Pre-Raphaelites: Beauty and Rebellion' (open till 5 June 2016). Unsurprisingly the art movement that portrayed the natural world in all its tiny detail, recreated the sheer exuberance of a rainbow beautifully; and our exhibition includes two fine examples. 'Walton-on-the-Naze' by Ford Madox Brown features Brown himself, along with his wife and child, taking in the view of the Essex coast. A dramatic rainbow arches across the width of the painting. But it's the painting by William Davis called 'The Rainbow', which depicts the fields of St. Helens and includes a vibrant rainbow streaking off to the right of the canvas, that interests me. Davis had only recently turned to landscape painting having formerly focused on portraiture, but his work was greatly admired by the London Pre-Raphaelites. Unfortunately for Davis the influential writer, John Ruskin and local critics were of a different opinion, and 'The Rainbow' received a scathing review, when it was exhibited in Liverpool in 1858. The Rainbow, about 1858 by William Davis (Walker Art Gallery, National Museums Liverpool) Assuming the rainbow was the reason behind this attack, Davis had the canvas rolled up so it couldn't be seen. It remained this way until the early 1970s. I can only imagine how exciting it must have been to discover this gorgeous rainbow hidden away for more than 100 years! Now the painting is on display in all its glory and thousands have people have enjoyed it in our exhibition. The exhibition catalogue includes more examples of Davis' work and Liverpool's role in the success of the Pre-Raphaelites.