European Stars and Stripes (Newspaper) - March 4, 1993, Darmstadt, Hesse                                Saving Stoner it Vij i a. It a a a Vav a o a a a it a a Quot Ltd Quot. A a it a s v 5 s. A \ a a \ l t i a a. J i i ,. I i h Quot to it y. H i 1 a a a a., it a jh--1 .4 up it it x a a 13 s of in if a a Vlf cd i  p a i a a i Jfe a to til ? a a a a a a k do life a. It i f w Juba a v .1. I via. 9 a fat. A y it he a m m we in a a  u 4 a he Jagta Mahshi 5 s s a a u ,11w a r i lib a a a a n. >0 v we it \ a 1 or i i r a h in or i -vv4 a s3fem a Ftp in a i a 4 v i i it w or. To,. T .,.,w. A x it ,0 s /4 v v a. A it it s  so a a a a a Ltd a. Lev a laser cleaning Means that fragile Stone it such As the chalks one at Amiens can survive a vigorous cleaning. F la discoveries create dilemma for restorers laser erases m centuries of grime by Patrick Mcdowell the associated press the laser crackles As Didier Groux Aims at the 700-year-old statue. In a Flash the beam lifts centuries of grime from the Queen of Sheba s Stone skirt. Quot this thing is marvelous Quot said Groux admiring a spotless Patch of off White Limestone which seconds earlier was a sooty Black. Quot it s the Only Way to  the experimental laser erasing caked on crud from the Virgin Mary s Portal at die Amiens Cathedral Marks what French scientists Call a major breakthrough in cleaning historic monuments Ana keeping them from crumbling. Unlike other Stone cleaning techniques a Micro sandblasting solvents and scrubbing a the resonating beam of a laser removes layers of dirt without touching the Stone beneath. This Means that fragile Stone such As the chalks one at Amiens can survive a vigorous cleaning without losing even the Fine layer of powder that one can lift off with the wipe of a Finger. The gentle cleaning has revealed traces of centuries old paint sparking debate on whether restoration should now also include bringing Back the original colors. Using 20th-Century technology on a 12th-Century masterpiece shows How practical lasers have become since a science fiction writers depicted them As sidearms for galactic swashbucklers. Quot everybody thinks of lasers As Ray guns. But there Are All kinds of lasers a to operate on Retinas to do Light shows or Industrial tasks Quot said Genevieve ortal a scientist at France s research Laboratory for historic monuments. The Laboratory employs about 20 scientists who diagnose the ills of France s venerable churches cathedrals and castles and then devise remedies. Degradation of Stone poses a major problem medieval masons preferred to work in easy to Cut soft Stone. Over the centuries War weather and nesting pigeons took their toll. But the decay of Stone accelerated Over the past 150 years because of industrialization the automobile and wide use of Coal. The resulting pollution especially in the Industrial Belt of Northern France eats away at soft Stone. In Amiens wind borne filth has been sticking to the Cathedral Walls and statuary for decades. The Black muck includes Coal soot car emissions tire dust bits of feathers and Bird dung. Traditional cleaning methods All damage the underlying Stone to some extent. Micro sandblasting for example can open a Hole in a sculpture hollowed out by hostile bacteria. That s Why about six years ago the research Laboratory began experimenting with lasers it invested several Hundred thousand dollars in the prototype first used at Amiens last summer. Like All lasers it works by Light stimulated by radiation emissions producing a tiny electromagnetic resonance. When Groux fires up his laser a heavy Box the size of a Small refrigerator he picks up a thick stainless steel Wand and Aims at the grime encrusted Stone. A red Dot illuminates the spot. Then Groux pushes a Button activating the laser and releasing invisible beams of Light that penetrate the layer of dirt the vibrations Nock it off in seconds. A plastic Sheet blocks off Croux s work site on the Cathedral s Western facade since a stray laser beam could destroy a passer by s Retina. Observers must Wear Eye Protection. Orial Hopes the laser can soon be used on stained Glass Wood plaster and other materials. Greeks working on the Pau Henon egyptians on the pyramids italians on Rome s Villa de Medicis plus German British Swiss and Canadian restorers All want to try the laser. But they will probably have to wait several years before the technology is generally used Oria said. The laser used to clean the Stone of the 12th-Century Cathedral in Amiens France has uncovered traces of 26 layers of paint or paint preparation that covered the Cathedral until the mid-18th Century. Armed with new information on the Cathedral s color scheme City officials Are talking about repainting the fagade in its original style. But what constitutes the Correct paint is it 15th Century or 17th Century won t any paint seem Garish for modern tastes accustomed to Bare Stone Quot you can t separate All these centuries of paint Quot said Vincent Brunelle the restoration project s chief architect he finds some Merit in painting part of the Portal to give modern visitors Quot an idea w Hen they View the fagade that it was once coloured. Until now there s been no  however no change will be undertaken without approval by International experts overseeing work on the Cathedral which is listed on Enesco s prestigious world heritage list. Experts consider the Amiens Cathedral the purest example of gothic architecture because it was erected quickly Between 1220 and 1288, in half the time it took to build notre Dame in Paris. Restoration has been going on almost constantly since the 14 the Century when the Cathedral was damaged in the Hundred years War with England. The current restoration project including repairing foundations cracks in the Walls and broken stained Glass has Cost $8 million since 1971. A Patrick Mcdowell 8 stripes Magazine March 4, 1993