Re: 4x5 halo (was: 4x5 camera suggestions

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

On 14 Feb 97 at 19:19, eml@xxxxxxxxx wrote:

> Finally, it hit me!  The film is made primarily for government contract
> use, and it has not been changed in years, even though halation wrecks
> the film's resolution.  Unless, that is, the film is intended to be exposed
> THROUGH THE BASE!  Exposing film through the base is not uncommon in some
> specialized applicarions. Then an "antireflection" layer would be preferable!
> 
> Now, think about your basic photochemistry.  Remember that a sensitizing
> dye ABSORBS the wavelengths of light to which it makes the film 
> sensitive!  Result?  HIE, when used with a red filter and when loaded
> "backwards" into the camera, with the emulsion against the pressure
> plate, effectively HAS an antihalation layer!  That layer is the 
> sensitizing-dye tinted emulsion, which supresses the REFLECTION
> of the very light that it absorbs!

Wouldn't one want to load Ektachrome IR backwards as well?
Would that work?
Would that work with any film, neg or slide, color or b&w?

Btw, I recently discovered another film without antihalation layer: 
the movie film sold by Seattle Film Works....8-))
 
> Now I know that there are those out there who are saying that Ed's
> not playing with a full deck, but I submit that it's the only plausible
> reason that I've been able to come up with in all the many years that I
> have volubly cursed HIE. 
> 
> Any comments?

Long term contracts as such is a very good reason, but I doubt it 
would have prevented the introduction of an antihalation layer (damn, 
from now on abbreviated to AHL) for such a long time.
Just look how many lines of Aerochrome IR we have now, and this film 
doesn't even have the quantity of sales HIE has (I think....might be 
different in the larger sizes....anyone?).




 
 
--
Bye,

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


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

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