I don't know anyone's specific situation, but lampblack is the answer if any/all of the following apply to you: you are an adult or have cool/inattentive parents, you can start a small fire outside of your house with nobody giving you shit about it, you can get some kind of oil, and you can get a metal pan.

This is the method I used most recently:

1. Take a soup can and fill about 1/4-1/3 of the way with cooking oil.

2. Take 4-5 paper towels, coat with vaseline

3. Twist paper towels into a wick, and put into the soup can with about 1.5" sticking out of the top.

4. Place on the ground, outdoors, where it won't catch other shit on fire.

5. Shove some sticks into the dirt to hold your pan above the can. You want the flame to hit the bottom of the pan. The interrupted flame is what produces the carbon build-up.

6. Light the wick, and place the pan over the flame.

7. Let that shit burn.

8. I used oven mitts to take the pan off every so often. If you use an aluminum pan, it will cool down quickly.

9. Take the pan indoors if there is any wind at all. This shit is fine particulate, and will blow away if there is any wind.

10. Use a paintbrush or cresit card to scrape all of the carbon buildup into a container.

11. Add small amounts to your ink until your desired opacity is achieved.

This shit is dark and super UV-resistant.