> Maybe I am missing something... I sometimes use mylar between my neg
> and my pt paper when printing. There is no difference in exposure
> times with or without mylar...
I was wondering about this too - mylar is a brand name for a polyester,
according to Light Impressions' catalog.
>From a very quick information search, it does appear that *mica* has some
level of opacity in the 400 to 700nm wavelength range.
Pete