RE: Halation

[George L Smyth <glsmyth@xxxxxxxxxxxxxxxxx>]

On Thu, 23 Sep 1999, ADavidhazy wrote:

> > If the film is being used for scientific purposes then it does need to be 
> > loaded in complete darkness. However, if you are developing it via E6 then 
> > subdued light is fine.
> 
> I am not sure I quite understand this. Loading in dark simply is associated
> with trying to prevent the film from being fogged or exposed. Would you not
> want the same degree of protection no matter how the film was processed?

When I spoke with Kodak a couple of years ago (preparing for my article on
EIR), I was told this.  The reason is that the AR-5 process will yield 
accurate infrared colors.  Developing EIR via E6 will not be as accurate.  

Most of us have noticed the hightened color saturation and contrast with
this film.  This is not the case when developing via AR-5 (also, the film
should be shot about a stop slower).  I also think that most people
probably shoot it a little faster than EI200 as a means of dealing with
this "problem."

I am going to guess that loading the film in subdued light actually does
fog the infrared layer to a certain extent.  Because this layer is the
middle of the three layers, it is somewhat protected (also, I believe that
EIR has an anti-halation layer, which helps protect it further.

If indeed there is slight fogging in the infrared layer, would we
recognize it?  Very probably not.  OTOH, if we were measuring the color
against a calibrated known, then we certainly would see the fogging.

Cheers -

george

---
Handmade Photographic Images
http://www2.ari.net/glsmyth/

*
****
*******
******************************************************
*  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  *
******************************************************