I have had the same experience. At least some acetate film will not be 
translucent.

Also, some very thin acetate tapes are barely translucent.

Marcos

Alan Lewis wrote:
> Several years ago, when I worked at the U.S. National Archives, we  tried 
> this "piped light test" with a few motion picture film stocks.  We  did not find 
> that acetate stock will pipe light and polyester stock won't  in all the 
> samples we tried.  We concluded that maybe the  photographic emulsion coated on the 
> base material had something to do with  light transmission but never did any 
> organized testing with all kinds  of emulsions (color, b/w, negative, 
> positive, mag stripe) on the two base  types.
>  
> Alan Lewis
> Washington, DC   
>
>
>
> **************************************See AOL's top rated recipes 
> (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004)
>