Updated on 25 March 2017 (Harvard referencing).
9 January 2017. “Listen” I said to little son a few days ago, “Why don’t you draw something for Anni to say thank you for being the wonderful aunt she is?” “Help” he replied, “I cannot think of anything. Tell me.” I had lots of ideas, none of them good enough for him. So I stopped. A day later he said: “I want to paint Mona Lisa for her. How do we start?”
He wanted to use the UV glow paint he had been given for Christmas, so it was to be a special Mona Lisa. With both our hands on one pencil we made a drawing first and coloured it in later, with UV light switched on all the time to see whether the effect would be there. My scanner was unable to reproduce some of the colours we used and it occurs to me now that I should have photographed it with the UV light on, so it looks pale in reproduction, but it was great fun to do and the mystery is all there ;o), so here it is (Fig. 1):