Why do some blackboard newspapers look like oil paintings? > ?

If it's legendary, look for professional chalk online. There are many colors, so it is not too difficult to draw this blue gradient. If you look closely, it is uneven and does not look like pigment, but the white part does not look like white chalk. It may be pigment-assisted, so I don't know if it is a color cast problem. You can practice the uniform gradient from white to black (black background on the blackboard) with white chalk, and then buy professional chalk after mastering the skills. Chalk drawing can also draw a very strong effect, close to complex pencil drawing.