I'd suggest pencil, as it doesn't contain any nasty chemicals that might do bad things to the canvas/image over time.
There might be certain pens that are suitable, not sure... hopefully someone else will jump in.
Charcoal is vulnerable to smudging, unless you use fixative to protect it. Not knowing what fixative contains (other than at least one chemical is toxic - usage outside not inside is recommended), I would be reluctant to use it on photographic prints without expert advice. |
