RE: Maco IR film base compared to Kodak HIE and Antihalation layers

["Rolland Elliott" <rolland_elliott@xxxxxxxxxxx>]

I thought MACO's reply to my recent post would interest people on this list, 
Check it out.  Peace Rolland Elliott


Dear Mr. Elliott

your eMail in regard of technical aspects of the MACO IR film has
been passed to us.
We are interested to receive any comprehensive customer feedback
directly.
The fastest way to reach us via email:

Photo@xxxxxxxx

Also, please visit our homepage:

www.mahn.net

Therefore, we take the opportunity to comment on some technical
aspects you reported about.

Any aspects in regard of the KODAK HIE film have to be commented by
KODAK themselves.
We will comment on some of your remarks about the MACO IR820c.

Base:
Measurements in regard of minimum fog level showed that the MACO IR 820c
has an extremely low fog level of D=0.06. Much to our knowledge this is
unsurpassed and accounts for comparatively short printing times (negatives)
and delivers high projection brilliance (slides).

Antihalation:
As you compared unprocessed MACO and Kodak film, if you would
have placed them in water, you could have seen, that the water will
get a greenish color cast - this is the antihalation dye
in the stage of dissolving.

Incorporating a water soluble antihalation dye, which is coated onto
the backside of the basematerial, into the MACO IR820c
has been carried out in order to keep halation phenomena to a minimum.
Halation will affect any type of film emulsion, regardless of their
sensitization - whether orthochromatic, panchromatic or infrared.

Ratio of Resolving power / IR sensitization:
Practical tests carried out in typical pictorial as well as technical/
scientific applications showed that the MACO IR820c under different
lighting conditions such as ambient (sun), tungsten or studio flash will
deliver high overall sharpness in combination with very fine grain.
Furthermore, halation phenomena are kept to a minimum. This is especially
important in application areas where high quality recording is necessary, 
such
as for criminal investigations in regard of counterfeit or forgery.

Depending on the type of camera filter being used, the incorporated
antihalation layer is also responsible for the comparatively high 
resolution.
Many photographers use infrared films with deep red instead of true IR 
filters.
Especially then, but of course in a.m. applications as well,
the antihalation will be a major technical advantage.
Also, it reduces the potential of camera film plate induced halation.

Film speed:
If film speed comparisons are carried out, it is important to install
a setup allowing for exact and identical testing parameters.
If you compare - compare with the same filters, the same effective
exposure values etc.

The MACO IR820c has an effective speed of ISO 100/21° without filter.
Depending on the type of filter used, film speed will drop by far.
The statement you made in regard of our film's speed vs. Kodak's lacks
major information (you mentioned different filters; type 87 vs 89b)

Direct visual comparisons between Kodak HIE and MACO IR820c show a
big difference in terms of graininess in favor to the MACO IR820c.
This is perhaps a hint that the KODAK HIE has a higher effective
speed than officially stated.
Of course this accounts for shorter possible exposure settings.

Reversal processing:

It is a known fact, that films reverse processed in Kodak's reversal
kit will deliver some kind of color cast !

In order to achieve best results in reversal processing by using
the KODAK reversal kit, it is important to carry out an optical
reversal (by light). This showed to deliver superior results
without the strong color cast you have encountered.
Since November 1999, practical tests have proven that all our
crystal clear polyester based films suited for reversal processing
(MACO ORT25, successor to the Agfaortho 25; PO100c, high res.
normal grade and our IR820c) will not show any strong color cast
if optical reversal is applied.
Moreover, the second problem in regard of reversal processing is
the fixing stage - we recommend to use LABOR PARTNER LP-FIX SUPRA
with high speed additive.

However, from our friends at TETENAL we have the information, that
a new reversal kit with optical reversal is currently under preparation.
It is supposed to be available in second half of April.

Best regards,
Markus Kohorst
MACO PHOTO PRODUCTS
6/3/2000+++

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