Re: HIE in 120/220

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On  2 Mar 00 at 22:53, PeteScherm@xxxxxxx wrote:

> Kodak did make 120 size IR short films (8 or 12 - can't remember - of the 
> 645-type format) during the 40's, but these had an anti-halation coating, 
> apparently, and thus eliminated the worry about light-tightness along the 
> edges.  The stock answer that Kodak gives is the difficulty of keeping the 
> light from "piping" through the entire film if a perfect seal between the 
> spool ends and the backing paper cannot be maintained.  I don't know if that 
> makes sense, but the net result is:  No anti-halation coating  equals too 
> risky a situation with roll film.  I would guess that 220 would be even less 
> likely.

I have heard a similar report about 120 format Kodak IR for the 
French defense department....but, as in your note above, I am not 
sure whether this was HIE or an older emulsion (the 'high speed' is 
not just a marketing gimmick, the predecessor was really slow, close 
to Konica (or even slower?). The same emulsion also came in an odd 
20-frame 135-20 format, with a long paper leader, thereby overcoming 
the problem of fogging with daylight loading.

Also, all arguments about 120 not being light-tight and fogging
around the edges is pure hogwash....apply the same to 35mm, and
Kodak would have to strike that format too, since it can only be 
loaded in the dark.

That said, the 120/220 format rolls supplied by Rolland Elliot don't
require the same caution when loading....the ordinary paper backing
he attaches (VPS I believe?) is plenty IR-proof, but it's indeed the
edges that require care....I loaded them in strong daylight
conditions high in the French Alps, but I will use a darkload bag
next time....a bit too much fogging around the edges (and the risk
of a non-aligned film in the Noblex panorama camera (it does that
with several brands/emulsions, but on normal emulsions the effect
isn't so severe).

































--                 
Bye,

Willem-Jan Markerink


      The desire to understand 
is sometimes far less intelligent than
     the inability to understand


<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]
*
****
*******
******************************************************
*  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  *
******************************************************