Make a list of things which can conduct electricity. I bet you won't have water color in your list but it can conduct electricity. Yes, you can with the multi meter you can also check its resistance.
Here, no conductive paint is used bu simple water color/ poster color is used.
But here I have used simple poster/water color and not Bare color.
Step 1: Materials Needed
1. 555 timer circuit
2. 2 x 10uF Capacitors
3. 1k resistance
5. Water color/Poster color
6. 9v Battery
Step 2: Creating the Circuit
The circuit is built around 555 timer I.C. I have used NE555 timer I.C. Assemble the components as shown in the circuit diagram on breadboard and ready the probes to put it on Paint.
Step 3: Testing It!
Attach the probes of multi meter at the terminals of Buzzer.
Take the probes and place both the probes on the line of the paint, You should here the first beep after some seconds. The time depends on how far you keep the probes. If the probes are nearer the time between both beeps. Then after some seconds you can listen second beep.
Both the beeps shows some different reading on multi meter. If the first beep shows 0.3v, then other shows around 5v. And if the first beep shows 5v, then the other beep shows 0.3v.
NOTE: YOU CAN USE ANY COLOR POSTER COLOR BUT THE COLOR SHOULD TAKE A BIG AMOUNT OF COLOR ON PAPER AND LET IT DRY!