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Kevin Matthews
Joined: 13 Apr 2004
Posts: 489
Location: Eugene, Oregon
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P.C.
millennium club
Joined: 26 May 2004
Posts: 2163
Location: Denmark
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 Posted: Fri Sep 22, 2006 2:46 am Post subject: |
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"From a distance, the perforations look slightly darker than the metal surfaces. The holes do not reflect light back to the viewer so they tend to darken the overall surface appearance. When light from behind is allowed to show through, the holes tend to lighten the surface appearance."
But this is not the whole truth --- fact is that with say two layers of perforated sheet , and light behind , a sort of inteference pattern show. Turning one layer of perforated sheet according to the other acturly produce sort od "inteference pattern" when light is thriwn thru the two layers.
Ofcaurse when a perforated sheet show -- hole,no hole,hole no hole aso X and Y vise , then if you place one simular sheet ontop you can move one sheet just slightly and the holes in one are covered by no hole in the other sheet ; moving it slightly again will open for the light to pass both holes in each layer ---- but this is not as interesting as when you turn one of the sheets ; that is when the pattern show ,and that pattern will change when you distance the two layers from each other .
Now some of the recent effects shown in the Silver Screen Galleri profit from this quite exiting effect ----- moving and twisting one layer of perforated alu sheet sort of entlargen the "holes" ; the pattern act as an vitural microscope , I know this is ilusions but realy it add an extra dimension to projected pictures, --- and in bigger scale it will act quite impressive ,when pattern details sort of continue in logic patterns down or up infinity as how I can see it work with projected light., --- just wanted to add this exiting fact about how perforated sheets work hands-on , try put some light behind two layers you be surprised; I realy suggest anyone who are looking for some real impressive display to buy just two small pieces of micro perforated Alu sheets , you can find these as model building in most shops where architects find their materials , but it is not before you cover one sheet with another turn one, and direct the light thru these, that these ilusions show. |
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