When you take a photo and zoom in, it’s unmistakable – it’s quite clear – but you do need to know what to look for, otherwise you won’t see it. My name is Maria Luise Ziltener-Fuiko; I’ve been a museum attendant here at the art museum for about 10 years and sometimes have time to look at the works in great detail. If you look more closely at this work by van Gogh, Soir d’été, the choice of colours immediately catches your eye. In fact, two-thirds of the painting is in this shade of yellow to copper-red – very vibrant – and you realise that on that evening, when van Gogh was determined to paint a large-format picture, a strong mistral must have been blowing; van Gogh painted this work en plein air, and you can even see his fingerprints. If you take a photograph of this spot at the top centre and then zoom in with your fingers, you can see it very, very clearly. Once you know this, you can see it with the naked eye too.