It’s a bit of a mystery isn’t it... someone could take charcoal sticks up there and rub them against the rock to perhaps better see the art – and being just charcoal (without any sort of binder) the charcoal would fairly easily wash away. But I wonder if someone hasn’t got the wrong end of the (charcoal) stick here.

Back in 2006 we discussed the Takuhon technique for recording rockart. Basically a Chinese or Japanese paper is placed over whatever is to be recorded and an impression of that is taken. The ink (charcoal+binder in this case) never comes into contact with the original and there is really little abrasive element involved (as there is in Western rubbings).

Not so with the fish (Gyotaku) technique where a charcoal+binder ink is applied directly to the object, and an impression of that is then taken on the paper. As the ink here has a (usually fatty) binder it will take longer to dissipate from the object.

The good news is that the binder in both cases is usually organic and will eventually break down (a few years depending on conditions) and once that happens the residue charcoal is free to dissipate naturally.