This is what happens when you put paper with an emulsion film in front of a powerful laser.
This image is of a burn mark from a piece of paper put in the Gemini laser at the Central Laser Facility. The burn mark is about 5cm across. Chris Hooker, a scientist at the facility, kindly spent a day with me letting me see what happens when you fire lasers at paper.
This paper is often used to see how clean the laser is - ie if there are hot or cold spots, diffraction, poor focusing etc. This infra-red laser is not at the final stage of the system, it gathers energy as it passes through titatnium saphires (excited with green lasers) and finally gets focused to a very small point and massively reduced in length (time of the pulse) before hitting a target. Where the laser is focused (at various places in the chain as well as the target area) and when it is compressed in time it must be in a vacuum. Various lenses that allow the laser to focus and the final target area is a very hard vacuum - air would be turned to plasma by the laser here - you would see sparks and energy would be lost.
Check out the video of this being made here: http://xray.test/node/7