Re: Infrared in questioned documents

[ADavidhazy <ANDPPH@xxxxxxxxxxxxxxxxxx>]

> I will use a Digital Back Phase One in a Hasselblad. I need to decide which
> filter for infrared should buy (here the filters are very expensive), and I
> would like to know which is the filter more adapted for this work type. If
> somebody has experience with analysis of documents it helps me. Should it be
> Wratten 88A or Wratten 87C?

My suggestion would be to get the deeper one, the 87C. Now, if you were doing
ir luminescence or fluorescence in the ir excited by visible then the 88A might
be a better choice. To do the latter you would also need a filter to block all
ir from your source though. IR luminescence is fantastic when it works!

Andrew  o o  0 0 o . o  Davidhazy, Imaging and Photo Tech
         \/\/\/\/\/\/          http://www.rit.edu/~andpph
__________|        |_____________________________________

*
****
*******
******************************************************
*  To remove yourself from this list, send:          *
*         UNSUBSCRIBE INFRARED                       *
*       to                                           *
*         MAJORDOMO@xxxxx                            *
*----------------------------------------------------*
*   For the IR-FAQ, IR-Gallery and heaps of links:   *
*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
******************************************************