How to take a photo of painting?

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I would appreciate a picture of an unknown author, written in chalk. Popal it to my mother in the 70's. Jews sold uezdzhaya in Israel. Already, perhaps, we can draw conclusions about the value of the painting. Still .... It shows the four girls of different ages and a dog. I only know that the author, a German (the Jews say). She still hangs framed on the wall. Maybe there and let them remain? How to make a photo?