I've tried the "soot" technique a few times over the years with no success. I finally took one more stab at it and got it to work. My next hurdle was finding a spray that would set the soot but not run or blur the image. Sounds easy? It was harder than the darn technique! LOL
To do the Soot Technique you need glossy cardstock (not photo paper as it will crack) and a cheap candle. This is one of the times you want to use one of those "emergency candles" – well isn't finding the right stuff to stamp with technically an "emergency"? Light the candle and carefully and quickly (smoothly, not too rushed) move your cardstock over the candle. The candle flame must touch the paper – if you get too close to the edges they will light on fire so you might want to do this technique near the sink with some water. Keep moving the paper over the flame until it's covered in soot. Remember to let the tip of the flame touch the paper.
Be careful not to touch the soot or you will leave finger prints and the soot will wipe off. Carefully stamp your image into the soot – where the rubber hits the soot it will remove it leaving the image. Very cool!
Your image must be set so that it permanently seals the soot. I tried hairspray and Workable Fixture – didn't work great – it blurred and ran over the image. I ended up finding an Acryllic Sealant which did the trick. Just make sure to spray outside because of the fumes.
Try it yourself – it's quite fun!