HIE Direct Positive Processing

[David Sprinkle <david-sprinkle@xxxxxxxx>]

Hi there,

First of all, I'm a new member of this list, so allow me to provide a
little information:

My name is David Sprinkle.  I am an electronics engineer with Toyota
Racing Development, helping to support the Toyota CART Indy-car engine
program.  I have been an enthusiastic amateur photographer for the last
four years.  I own a collection of Canon FD equipment and a Yashica
Mat-124.  I have recently become interested in IR photography, mostly
due to the striking images I've seen on some of the list-members'
websites.  Your use of IR film's black skies, white foliage, and
heightened contrast is reminiscent of Ansel's work, only you get the
effect without a dodging wand.

Secondly, I suspect that this topic has probably been discussed to death
on this newsgroup, so please accept my apology for bringing it up
again.  However, I only yesterday subscribed to the group, and as a
result don't have the benefit of previous conversation about the topic.

A few months ago, I read Jim Henderson's posting (dated 31 July, 1996)
to w.j.markerink@xxxxx in which he describes the speed gains
available from Kodak's HIE infrared when processed with Kodak's T-Max
direct positive kit.  Yesterday, I tested the procedure and didn't
realize the results he (and others, such as Harald Leban) have found. 
Please allow me to describe my procedure and results.  Perhaps someone
could point out any problems.

1.  Exposure:
I exposed three rolls of HIE film.  Each roll was identically exposed
and consisted of 19 exposures of a Kodak gray-scale target.  The target
was illuminated with four tungsten bulbs.  Although I realize that
visible-light meter readings are suspect when shooting infrared, an
in-camera meter indicated a proper exposure of 1/8s, f4 for ASA50.  Each
successive exposure was a 1-stop decrease from the previous frame.  The
film was exposed as follows:
	1	1s, f1.4
	2	1s, f2
	3	1s, f2.8
	4	1s, f4
	5	1s, f5.6
	6	1s, f8
	7	1s, f11
	8	1s, f16
	9 	1/250s, f1.4
	10	1/250s, f2
	11	1/250s, f2.8
	12	1/250s, f4
	13	1/250s, f5.6
	14	1/250s, f8
	15	1/250s, f11
	16	1/250s, f16
	17	1/2000s, f8
	18	1/2000s, f11
	19	1/2000s, f16	
Equipment used was a Canon F1n mounted on a Bogen tripod and an
FD85/1.2L lens.

2.  Development:
The control roll was developed in D-76 per Kodak's recommendations for
HIE film.  The first test roll was developed in Kodak's T-Max direct
positive kit, per Kodak's instructions for T-Max 100.  The second test
roll was also developed in the T-Max direct positive kit, with the only
change being the addition of sodium sulfite to the first developer (as
per Kodak and  Jim Henderson's recommendation for enhancing contrast).

3.  Results:
The three different processes seem to result in approximately the same
speed.  In each case, the proper exposure appeared to be frame 10
(1/250s, f2).  I saw no speed difference at all, not even one stop. 
This is far different from the 4 to 6 stop speed increase Jim Henderson
and Harald Laban observed.

Quite frankly, this is baffling to me.  I have no idea why I haven't
been able to measure the speed gains others claim to have seen with the
direct positive technique.  Am I missing something here?  Does anyone
out there have any additional insight?

Thanks for any information.

-dave sprinkle
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