Lasers in Training

Shots fired:

"There is a sizzle as a white "I was here" message is burned off the grey stone by the 56-year old... ."

"The laser evaporates the graffiti, without damaging the stone underneath," Daniela Valentini, who heads up the Angels' team of cultural heritage restorers, told AFP as she pointed the fibre laser's beam at a scrawled signature.

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The word graffiti comes from "sgraffito", which comes from "to scratch". It referred to the scratching away of residue to reveal the surface underneath. There's a great modern example of this where artists leave their mark by removing decades-deep layers of dirt on city walls. It's called "reverse graffiti", although it's more closely related to the original word than spraypainting a subway car. In fact, most of us are guilty of this kind of graffiti. "Wash Me" written on a dirty window anyone? Running your finger through beads of condensation on a wet window? 

Graffiti took a hard turn with the advent of aerosol spray paint. A revolutionary turn. Spray paint changed everything. It also made graffiti a lot harder to remove. Before, you removed the graffiti by cleaning the surface. It was, in a way, a public service, a nudge. Now we need powerful solvents and specially-engineered surfaces to keep it under control. Graffiti is now a costly nuisance for property owners (but not hip marketing hustlers, or millenial-hungry municipalities with a couple empty walls in their downtown.)

Blazing past the harsh chemical treatments of the past, we've now entered the new era of graffiti removal. It might seem like overkill to burn it off with a laser, but this technique does help to preserve the defaced surface, since it only takes off the very top layer of the graffiti and nothing else.

But, as all things go, as fire fights fire, we have to wonder how this could evolve. Let's imagine that graffiti artists start using lasers the way the way they did spraypaint in the 1970's; what would that mean?

Then again, let's not think too hard. GRL already showed us what lasers can do. So did the sticky LED throwies that shut down Boston for a minute after glowing pictures of Aqua Teen Hunger Force showed up all over the place. 

Image source: Gareth Emery's Laserface via Dancing Astronaut

Notes:
World's first graffiti-busting laser helps Florence's 'Angels'
March 2019, phys.org

Graffiti Research Labs

US - Marines to buy 1,653 eye-safe laser dazzlers
May 2018, Laser Pointer Safety

Safety features include infrared light emission to detect your distance to it, and to reduce the output accordingly.

Can't say no to this:
Scotland - Scientists develop way to shoot laser light from eyes
May 2018, Laser Pointer Safety

Researchers have developed a membrane-thin laser emitter, widely reported in the press with headlines such as “Scientists Create Superman-like Eye Lasers.” When pumped by outside light, the membrane re-emits spectrally pure laser light.