Carbon from wood routinely is 'charcoal', which is not plain C. It has semi-volatile plant matter attached to it, which is why it's used in pyrotechnics. Trying making black powder with activated charcoal (pretty close to C), and it's horrible. Make it with regular charcoal, and it's excellent. Depending on what you burn to make your charcoal, you can get better or worse material. You can also over-cook charcoal and drive off most flammable organic matter, making closer to C. Much of what you see with the 'stickiness' of the black on paper are the oils and other materials adsorbed onto the carbon surface that are sticky. There's whole books written on making charcoal--take a look online and you can read about making your own charcoal. Should give you some more insight.